Novel coordination complexes and process of producing polycarbonate by copolymerization of carbon dioxide and epoxide using the same catalyst

ABSTRACT

Provided are a complex prepared from ammonium salt-containing ligands and having such an equilibrium structural formula that the metal center takes a negative charge of 2 or higher, and a method for preparing polycarbonate via copolymerization of an epoxide compound and carbon dioxide using the complex as a catalyst. When the complex is used as a catalyst for copolymerizing an epoxide compound and carbon dioxide, it shows high activity and high selectivity and provides high-molecular weight polycarbonate, and thus easily applicable to commercial processes. In addition, after forming polycarbonate via carbon dioxide/epoxide copolymerization using the complex as a catalyst, the catalyst may be separately recovered from the copolymer.

TECHNICAL FIELD

The present invention relates to a novel catalyst for use in preparingpolycarbonate from an epoxide compound and carbon dioxide and a methodfor preparing polycarbonate using the same. More particularly, thepresent invention relates to a catalyst for preparing the above polymer,which includes a complex having such an equilibrium structural formulathat the metal center of the complex takes a negative charge of 2 orhigher, as well as to a method for preparing polycarbonate viacopolymerization of carbon dioxide and epoxide using the same complex asa catalyst. In addition, the present invention relates to a methodincluding carrying out polymerization using the above catalyst, andseparately recovering the catalyst from the solution in which theresultant copolymer and the catalyst are dissolved.

BACKGROUND ART

Aliphatic polycarbonate is an easily biodegradable polymer and is usefulfor packaging or coating materials, etc. Processes for preparingpolycarbonate from an epoxide compound and carbon dioxide is highlyeco-friendly in that they use no harmful compound, phosgene, and adopteasily available and inexpensive carbon dioxide.

Since 1960's, many researchers have developed various types of catalyststo prepare polycarbonate from an epoxide compound and carbon dioxide.Recently, we have developed a catalyst for carrying out carbondioxide/epoxide copolymerization. The catalyst includes a complex havingan onium salt and a metal center with a Lewis acid group in onemolecule. Use of the catalyst allows the growth point of the polymerchain to be positioned always in the vicinity of the metal in thepolymerization medium for carrying out epoxide/carbon dioxidecopolymerization, regardless of the concentration of the catalyst. Inthis manner, the catalyst shows high activity even under a high ratio ofmonomer/catalyst, exhibits high cost-efficiency by virtue of a decreasein catalyst need, and provides polycarbonate with a high molecularweight. Moreover, the catalyst realizes polymerization activity even athigh temperature to increase the conversion, permits easy removal of thepolymerization reaction heat, and thus is easily applicable tocommercial processes [see, Korean Patent Application No. 10-2007-0043417(May 4, 2007, Title: COORDINATION COMPLEXS CONTAINING TWO COMPONENTS INA MOLECULE AND PROCESS OF PRODUCING POLYCARBONATE BY COPOLYMERIZATION OFCARBON DIOXIDE AND EPOXIDE USING THE SAME); International PatentApplication No. PCT/KR2008/002453; Eun Kyung Noh, Sung Jae Na, Sujith S,Sang-Wook Kim, and Bun Yeoul Lee* J. Am. Chem. Soc. 2007, 129, 8082-8083(2007 Jul. 4)]. Further, when the complex having an onium salt and ametal center with a Lewis acid group in one molecule is used as acatalyst for carbon dioxide/epoxide copolymerization, the catalyst iseasily separated and reutilized from the copolymer after thepolymerization. Thus, such a method for separately recovering thecatalyst has been described in a patent application and a journal[Korean Patent Application No. 10-2008-0015454 (Feb. 20, 2008, Title:METHOD FOR RECOVERING CATALYST FROM PROCESS FOR PREPARING COPOLYMER);Bun Yeol Lee, Sujith S, Eun Kyung Noh, Jae Ki Min, “A PROCESS PRODUCINGPOLYCARBONATE AND A COORDINATION COMPLEXES USED THEREFOR”PCT/KR2008/002453 (2008 Apr. 30); Sujith S, Jae Ki Min, Jong Eon Seong,Sung Jea Na, and Bun Yeoul Lee* “A HIGHLY ACTIVE AND RECYCLABLECATALYTIC SYSTEM FOR CO₂/(PROPYLENE OXIDE) COPOLYMERIZATION” Angew.Chem. Int. Ed., 2008, 47, 7306-7309].

The complex of the above studies mainly includes Salen-cobalt compound([H₂Salen=N,N′-bis(3,5-dialkylsalicylidene)-1,2-cyclohexanediamine])(see the following chemical formula), obtained from a Schiff base ligandof a salicylaldehyde compound and a diamine compound. The complex is atetradentate (or quadradendate) cobalt compound-based complex in whichtrivalent cobalt atom is coordinated with two nitrogen imine ligands andtwo phenolate ligands at the same time:

The complex may be referred to as a tetradentate (or quadradendate)Schiff base complex, and may be prepared according to the followingreaction scheme:

The above tetradentate (or quadradentate) Schiff-base cobalt or chromecomplex has been developed intensively as a carbon dioxide/epoxidecopolymerization catalyst. (Cobalt-based catalyst: (a) Lu, X.-B.; Shi,L.; Wang, Y.-M.; Zhang, R.; Zhang, Y.-J.; Peng, X.-J.; Zhang, Z.-C.; Li,B. J. Am. Chem. Soc. 2006, 128, 1664. (b) Cohen, C. T. Thomas, C. M.Peretti, K. L. Lobkovsky, E. B. Coates, G. W. Dalton Trans. 2006, 237.(c) Paddock, R. L. Nguyen, S. T. Macromolecules 2005, 38, 6251.Chrome-based catalyst: (a) Darensbourg, D. J.; Phelps, A. L.; Gall, N.L.; Jia, L. Acc. Chem. Res. 2004, 37, 836. (b) Darensbourg, D. J.;Mackiewicz, R. M. J. Am. Chem. Soc. 2005, 127, 14026.).

DISCLOSURE Technical Problem

We have studied about the characteristics and structures of thetetradentate (or quadradentate) complex having the above describedstructure and unexpectedly found that the complex shows significantlydifferent activities and selectivities depending on the R group. Inorder word, when R is a sterically hindered group such as t-butyl, thecompound shows commonly expectable activity and selectivity. However,when R has decreased steric hindrance, or R is a radical such as methyl,the complex provides an activity (TOE, turnover frequency) of 26000 h⁻¹,which is about 20 times higher than the activity (1300 h⁻¹) of thecorresponding t-butyl group-containing complex. In addition, the methylgroup-containing complex provides an increase in selectivity from 84% to99% or higher. Based on these findings, we have conducted several typesof structural analysis including ¹H NMR, ¹³C NMR, ¹⁵N NMR, ¹⁹F NMR, IR,IAP-AES, elemental analysis, electrochemical analysis, etc. As a result,we have found that when R is a less sterically hindered radical, such asmethyl, another complex (i.e. bidentate complex) having a differentstructure in which the metal is not coordinated with the adjacentnitrogen is obtained, and the complex has high activity and selectivity.

Therefore, an object of the present invention is to provide a method forcopolymerizing carbon dioxide and epoxide using a complex coordinatedwith monodentate, bidentate or tridentate ligands having at least oneprotonated group rather than the existing tetradentate (orquadradentate) complex.

Another object of the present invention is to provide a method for theformation of a copolymer using the above complex as a catalyst, and forthe separation and recovery of the catalyst from the mixed solution ofthe resultant copolymer and the catalyst.

Still another object of the present invention is to provide theabove-described novel complex.

Technical Solution

To achieve the object of the present invention, the present inventionprovides a novel complex coordinated with monodentate, bidentate ortridentate ligands having at least one protonated group, and a methodfor preparing a carbon dioxide/epoxide copolymer using the same complexas a catalyst.

Hereinafter, the present invention will be explained in more detail.

The present invention provides a novel complex as a catalyst forpreparing a carbon dioxide/epoxide copolymer. The complex is coordinatedwith monodentate, bidentate or tridentate ligands having at least oneprotonated group. The complex is represented by Chemical Formula 1:

[L_(a)MX_(b)]X_(c)  [Chemical Formula 1]

wherein

M represents a metal element;

L represents a L-type or X-type ligand;

a represents 1, 2 or 3, wherein when a is 1, L includes at least twoprotonated groups, and when a is 2 or 3, L(s) are the same or different,and may be linked to each other to be chelated to the metal as abidentate or tridentate ligand, with the proviso that at least one Lincludes at least one protonated group and the total number ofprotonated groups contained in L(s) is 2 or more;

X(s) independently represent a halide ion; BF₄ ⁻, ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻:HCO₃ ⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms; and

b and c satisfy the condition of “(b+c)=(total number of protonatedgroups contained in L)+[(oxidation number of metal)−(number of X-typeligands in L)]”.

The anion of Meisenheimer salt is a compound having the followingstructural formula:

wherein

R represents methyl or H; and

R′ is selected from H and nitro (—NO₂), with the proviso that at leastone of the five R′ radicals represents nitro (—NO₂).

In Chemical Formula 1, L-type and X-type ligands are described in detailin [Gray L. Spessard and Gary L. Miessler, Organometallic Chemistry,published by Prentice Hall, p. 46]. L-type ligands mean neutral ligandsand particularly include non-paired electron pair donors, such asphosphine, pi-bond donors, such as ethylene, or sigma-bond donors, suchas hydrogen. L-type ligands are bound to the metal by donatingnon-paired electron pairs, and binding of the L-type ligands has noeffect on the oxidation number of the metal. X-type ligands includeanionic ligands, such as chlorine or methyl. Binding of such X-typeligands is regarded as binding between X⁻ anion and M⁺ cation, andaffects the oxidation number of the metal.

The complex used as a carbon dioxide/epoxide copolymerization catalystherein is a complex coordinated with monodentate, bidentate ortridentate ligands having at least one protonated group (i.e. complexrepresented by Chemical Formula 1), and having such an equilibriumstructural formula that the metal center takes a negative charge of 2 orhigher. The carbon dioxide/epoxide copolymerization catalysts developedto date are tetradentate (or quadradentate) Schiff-base complexeswherein “four groups are bound to one metal atom”, and thus are clearlydifferent from the complex disclosed herein.

According to one embodiment of the present invention, there is provideda complex represented by Chemical Formula 1, wherein the protonatedgroup contained in L represents a functional group represented byChemical Formula 2a, 2b or 2c, and M represents cobalt (III) or chromium(III):

wherein

G represents a nitrogen or phosphorus atom;

R¹¹, R¹², R¹³, R²¹, R²², R²³, R²⁴ and R²⁵ independently represent a(C1-C20)alkyl, (C2-C20)alkenyl, (C1-C15)alkyl(C6-C20)aryl or(C6-C20)aryl(C1-C15)alkyl radical with or without at least one ofhalogen, nitrogen, oxygen, silicon, sulfur and phosphorus atoms; or ahydrocarbyl-substituted metalloid radical of a Group 14 metal, whereintwo of R¹¹, R¹² and R¹³, or two of R²¹, R²², R²³, R²⁴ and R²⁵ may belinked to each other to form a ring;

R³¹, R³² and R³³ independently represent a hydrogen radical;(C1-C20)alkyl, (C2-C20)alkenyl, (C1-C15)alkyl(C6-C20)aryl or(C6-C20)aryl(C1-C15)alkyl radical with or without at least one ofhalogen, nitrogen, oxygen, silicon, sulfur and phosphorus atoms; or ahydrocarbyl-substituted metalloid radical of a Group 14 metal, whereintwo of R³¹, R³² and R³³ may be linked to each other to form a ring;

X′ represents an oxygen atom, sulfur atom or N—R (wherein R represents ahydrogen radical; or a (C1-C20)alkyl, (C2-C20)alkenyl,(C1-C15)alkyl(C6-C20)aryl or (C6-C20)ar(C1-C15)alkyl radical with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms; and

the alkyl of the alkyl, alkenyl, alkylaryl or aralkyl radicals may belinear or branched.

According to another embodiment of the present invention, there isprovided a complex represented by Chemical Formula 1, wherein Lrepresents a ligand represented by Chemical Formula 3, a represents 2 or3, and M represents cobalt (III) or chromium (III):

wherein

A represents an oxygen or sulfur atom;

R¹ through R⁵ independently represent a hydrogen radical; linear orbranched (C1-C20)alkyl, (C2-C20)alkenyl, (C1-C15)alkyl(C6-C20)aryl or(C6-C20)aryl(C1-C15)alkyl radical with or without at least one ofhalogen, nitrogen, oxygen, silicon, sulfur and phosphorus atoms; or ahydrocarbyl-substituted metalloid radical of a Group 14 metal, whereinthe alkyl or alkenyl of R³ may be further substituted by a(C1-C15)alkyl(C6-C20)aryl or (C6-C20)aryl(C1-C15)alkyl, two of R¹through R⁵ may be linked to each other to form a ring, and at least oneof R¹ through R⁵ include at least one of Chemical Formulas 2a to 2c;

a represents 2 or 3; and

L(s) are the same or different and may be linked to each other to bechelated to the metal as a bidentate or tridentate ligand.

According to still another embodiment of the present invention, there isprovided a complex having two ligands L represented by Chemical Formula4:

wherein

B¹ through B⁴ independently represent (C2-C20)alkylene or(C3-C20)cycloalkylene;

R²⁶ represents primary or secondary (C1-C20)alkyl;

R²⁷ through R²⁹ are independently selected from (C1-C20)alkyl and(C6-C30)aryl;

Q represents a divalent organic bridge group for linking the twonitrogen atoms with each other; and

the alkylene or alkyl may be linear or branched.

More particularly, in Chemical Formula 4, Q represents (C6-C30)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, wherein thearylene, alkylene, alkenylene, alkynylene, cycloalkylene or fusedcycloalkylene may be further substituted by a substituent selected fromhalogen atoms, (C1-C7)alkyl, (C6-C30)aryl and nitro groups, or mayfurther include at least one hetero atom selected from O, S and N.

Preferably, in Chemical Formula 4, B¹ through B⁴ independently representpropylene, R²⁶ and R²⁷ independently represent methyl, R²⁸ and R²⁹independently represent butyl, and Q represents trans-1,2-cyclohexylene.

The ligand represented by Chemical Formula 4 may be formed from a phenolderivative represented by Chemical Formula 14, which is prepared fromthe reaction between a phenol compound represented by Chemical Formula15 and substituted by an alkyl group at the C2 position and a tertiaryalcohol compound represented by Chemical Formula 16 in the presence ofan acid catalyst:

In Chemical Formulas 14 to 16, B⁹ and B¹⁰ independently represent(C2-C20)alkylene or (C3-C20)cycloalkylene, preferably propylene. R²⁶represents primary or secondary (C1-C20)alkyl. When R²⁶ is a tertiaryalkyl, the reaction provides a low yield due to the production ofbyproducts caused by various side reactions, and thus requires apurification process for removing the byproducts. In addition, cobaltcomplexes obtained from such a tertiary alkyl-containing phenol compoundhave a different structure and low activity. Thus, primary or secondary(C1-C20)alkyl is preferred. More particularly, R²⁶ represents primary orsecondary (C1-C7)alkyl. Herein, the term ‘primary alkyl’ includes normalalkyl, neo-alkyl or iso-alkyl. The terms ‘secondary alkyl’ and ‘tertiaryalkyl’ are also referred to as ‘sec-alkyl’ and led-alkyl', respectively.

R²⁷ is selected from (C1-C20)alkyl and (C6-C30)aryl, more particularly(C1-C7)alkyl, and preferably methyl. The term ‘alkyl’ includes a linearor branched alkyl group.

X³ and X⁴ is independently selected from Cl, Br and I.

Herein, the term ‘aryl’ includes an aromatic ring, such as phenyl,naphthyl, anthracenyl or biphenyl, wherein a carbon atom in the aromaticring may be substituted by a hetero atom, such as N, O and S.

As the acid catalyst, AlCl₃ or an inorganic acid, such as phosphoricacid or sulfuric acid, may be used. A solid acid catalyst may be used topermit recycle of the catalyst after the reaction. Particular examplesof the solid acid catalyst include Nafion NR50, Amberlyst-15, H-ZSM5,H-Beta, HNbMoO₆, or the like (see, Kazunari Domen et. al, J. AM. CHEM.SOC. 2008, 130, 7230-7231).

The tertiary alcohol compound represented by Chemical Formula 16 may beprepared by various organic reactions. For example, the tertiary alcoholcompound may be obtained according to Reaction Scheme 7:

wherein

X³, X⁴ and R²⁷ are the same as defined in Chemical Formula 16.

The present invention also provides a ligand compound represented by

Chemical Formula 17 prepared from a phenol derivative represented byChemical Formula 14:

In Chemical Formula 17, B¹ through B⁴ independently represent(C2-C20)alkylene or (C3-C20)cycloalkylene, preferably propylene. Thealkylene may be linear or branched.

In Chemical Formula 17, R²⁶ represents primary or secondary(C1-C20)alkyl. When R²⁶ is tertiary alkyl, the reaction provides a lowyield due to the production of byproducts caused by various sidereactions, and thus requires a purification process for removing thebyproducts. In addition, cobalt complexes obtained from such a tertiaryalkyl-containing phenol compound have a different structure and lowactivity. Thus, primary or secondary (C1-C20)alkyl is preferred. Moreparticularly, R²⁶ represents primary or secondary (C1-C7)alkyl. Mostpreferably, R²⁶ represents methyl.

In Chemical Formula 17, R²⁷ through R²⁹ are independently selected from(C1-C20)alkyl and (C6-C30)aryl groups. More particularly, R²⁷ throughR²⁹ are independently selected from (C1-C7)alkyl groups. Preferably, R²⁷represents methyl and R²⁸ and R²⁹ independently represent butyl.

In Chemical Formula 17, Q represents a divalent organic bridge group forlinking the two nitrogen atoms with each other. Particularly, Qrepresents (C6-C30)arylene, (C1-C20)alkylene, (C2-C20)alkenylene,(C2-C20)alkynylene, (C3-C20)cycloalkylene or fused(C3-C20)cycloalkylene, wherein the arylene, alkylene, alkenylene,alkynylene, cycloalkylene or fused cycloalkylene may be furthersubstituted by a substituent selected from halogen atoms, (C1-C7)alkyl,(C6-C30)aryl and nitro groups, or may further include at least onehetero atom selected from O, S and N. More particularly, Q is selectedfrom ethylene, trans-1,2-cyclohexylene and 1,2-phenylene.

In Chemical Formula 17, Z⁻(s) are independently selected from halideions, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻, and PF₆ ⁻, more particularly iodide ion andBF₄ ⁻.

More preferably, the ligand compound represented by Chemical Formula 17may be a ligand compound represented by Chemical Formula 18:

In Chemical Formula 18, m and n independently represent an integer from1 to 19, preferably from 1 to 5, and more preferably 2.

In Chemical Formula 18, R²⁶ represents primary or secondary(C1-C20)alkyl. When R²⁶ is a tertiary alkyl, the reaction provides a lowyield due to the production of byproducts caused by various sidereactions, and thus requires a purification process for removing thebyproducts. In addition, cobalt complexes obtained from such a tertiaryalkyl-containing compound have a different structure and low activity.Thus, primary or secondary (C1-C20)alkyl is preferred. Moreparticularly, R²⁶ represents primary or secondary (C1-C7)alkyl. Mostpreferably, R²⁶ represents methyl.

In Chemical Formula 18, R²⁷ through R²⁹ are independently selected from(C1-C20)alkyl and (C6-C30)aryl groups. More particularly, R²⁷ throughR²⁹ are independently selected from (C1-C7)alkyl groups. Preferably, R²⁷represents methyl and R²⁸ and R²⁹ independently represent butyl.

In Chemical Formula 18, Q represents a divalent organic bridge group forlinking the two nitrogen atoms with each other. Particularly, Qrepresents (C6-C30)arylene, (C1-C20)alkylene, (C2-C20)alkenylene,(C2-C20)alkynylene, (C3-C20)cycloalkylene or fused(C3-C20)cycloalkylene, wherein the arylene, alkylene, alkenylene,alkynylene, cycloalkylene or fused cycloalkylene may be furthersubstituted by a substituent selected from halogen atoms, (C1-C7)alkyl,(C6-C30)aryl and nitro groups, or may further include at least onehetero atom selected from O, S and N. More particularly, Q is selectedfrom ethylene, trans-1,2-cyclohexylene and 1,2-phenylene.

In Chemical Formula 18, Z⁻(s) are independently or simultaneouslyselected from halide ions, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻, and PF₆ ⁻, moreparticularly iodide ion and BF₄ ⁻.

A method for preparing the compound represented by Chemical Formula 17or 18 includes:

adding a diamine compound to a compound represented by Chemical Formula20 to perform imination and to produce a compound represented byChemical Formula 21; and

adding a tertiary amine compound thereto to produce a compoundrepresented by Chemical Formula 17:

In Chemical Formulas 17, 20 and 21, B¹ through B⁴, B⁹ and B¹⁰independently represent (C2-C20)alkylene or (C3-C20)cycloalkylene,preferably (C2-C6)alkylene, more preferably propylene;

R²⁶ represents primary or secondary (C1-C20)alkyl, preferably primary orsecondary (C1-C7)alkyl, more preferably methyl;

R²⁷ through R²⁹ are independently selected from (C1-C20)alkyl and(C6-C30)aryl groups, preferably (C1-C7)alkyl groups. More preferably,R²⁷ represents methyl and R²⁸ and R²⁹ independently represent butyl;

Q represents a divalent organic bridge group for linking the twonitrogen atoms with each other, preferably Q represents (C6-C30)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, wherein thearylene, alkylene, alkenylene, alkynylene, cycloalkylene or fusedcycloalkylene may be further substituted by a substituent selected fromhalogen atoms, (C1-C7)alkyl, (C6-C30)aryl and nitro groups, or mayfurther include at least one hetero atom selected from O, S and N, andmore preferably, Q represents trans-1,2-cyclohexylene;

Z⁻(s) are independently selected from halide ions, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻and PF₆ ⁻, more particularly iodide ion and BF₄ ⁻; and

X³ and X⁴ are independently selected from Cl, Br and I.

The compound represented by Chemical Formula 20 may be prepared byreacting the compound represented Chemical Formula 15 with the compoundrepresented by Chemical Formula 16 in the presence of an acid catalystto form the compound represented by Chemical Formula 14, and byattaching an aldehyde group at the compound represented by ChemicalFormula 14. The acid catalyst may be selected from AlCl₃, inorganicacids and solid acid catalysts.

According to one embodiment of the complex represented by ChemicalFormula 1, there is provided a complex represented by Chemical Formula5:

wherein

A¹ and A² independently represent an oxygen or sulfur atom;

X(s) independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻;HCO₃ ⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms;

R⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁵ and R⁴⁶ are independently selected from H,tert-butyl, methyl, ethyl, isopropyl and —[YR⁵¹_(3-m){(CR⁵²R⁵³)_(n)N⁺R⁵⁴R⁵⁵R⁵⁶}_(m)], with the proviso that at leastone of R⁴¹, R⁴², R⁴³, R⁴⁴, R⁴⁵ and R⁴⁶ represents —[YR⁵¹_(3-m){(CR⁵²R⁵³)_(n)N⁺R⁵⁴R⁵⁵R⁵⁶}_(m)] (wherein Y represents a carbon orsilicon atom, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵ and R⁵⁶ independently represent ahydrogen radical; (C1-C20)alkyl, (C2-C20)alkenyl, (C1-C15)alkyl(C6-C20)aryl or (C6-C20)ar(C1-C15)alkyl radical with or without at least one ofhalogen, nitrogen, oxygen, silicon, sulfur and phosphorus atoms; or ahydrocarbyl-substituted metalloid radical of a Group 14 metal, whereintwo of R⁵⁴, R⁵⁵ and R⁵⁶ may be linked to each other to form a ring; mrepresents an integer from 1 to 3; and n represents an integer from 1 to20); and

b+c−1 represents an integer that equals to the sum of m values of thetotal —[YR⁵¹ _(3-m){(CR⁵²R⁵³)_(n)N⁺R⁵⁴R⁵⁵R⁵⁶}_(m)] radicals contained inthe complex represented by Chemical Formula 5.

Preferably, in the complex represented by Chemical Formula 5, R⁴¹, R⁴³,R⁴⁴ and R⁴⁵ are independently selected from tert-butyl, methyl, ethyland isopropyl; R⁴² and R⁴⁶ independently represent —[CH{(CH₂)₃N⁺Bu₃}₂]or —[CMe{(CH₂)₃N⁺Bu₃}₂]; and b+c represents 5.

According to another embodiment of the complex represented by ChemicalFormula 1, there is provided a complex represented by Chemical Formula6:

wherein

A¹ and A² independently represent an oxygen or sulfur atom; X(s)independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻; HCO₃⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms;

R⁶² and R⁶⁴ are independently selected from tert-butyl, methyl, ethyl,isopropyl and hydrogen, and R⁶¹ and R⁶³ independently represent —[YR⁵¹_(3-m){(CR⁵²R⁵³)_(n)N⁺R⁵⁴R⁵⁵R⁵⁶}_(m)] (wherein Y represents a carbon orsilicon atom, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵ and R⁵⁶ independently represent ahydrogen radical; (C1-C20)alkyl, (C2-C20)alkenyl,(C1-C15)alkyl(C6-C20)aryl or (C6-C20)ar(C1-C15)alkyl radical with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms; or a hydrocarbyl-substituted metalloid radical of aGroup 14 metal, wherein two of R⁵⁴, R⁵⁵ and R⁵⁶ may be linked to eachother to form a ring; m represents an integer from 1 to 3; and nrepresents an integer from 1 to 20);

b+c−1 represents an integer that equals to 2×m; and

A³ represents a chemical bond or divalent organic bridge group forlinking the two benzene rings.

More particularly, A³ represents a chemical bond, (C6-C30)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, or —Si(R⁸⁷)(R⁸⁸)—,—CH═N-Q-N═CH— or the arylene, alkylene, alkenylene, alkynylene,cycloalkylene or fused cycloalkylene may be further substituted by asubstituent selected from halogen atoms, (C1-C7)alkyl, (C6-C30)aryl andnitro groups, or may further include at least one hetero atom selectedfrom O, S and N, wherein R⁸⁷ and R⁸⁸ independently represent(C1-C20)alkyl, (C3-C20)cycloalkyl, (C1-C15)alkyl(C6-C20)aryl, or(C6-C20)ar(C1-C15)alkyl, and Q includes a divalent organic bridge groupfor linking the two nitrogen atoms. Particularly, Q represents(C6-C30)arylene, (C1-C20)alkylene, (C2-C20)alkenylene,(C2-C20)alkynylene, (C3-C20)cycloalkylene or fused(C3-C20)cycloalkylene, wherein the arylene, alkylene, alkenylene,alkynylene, cycloalkylene or fused cycloalkylene may be furthersubstituted by a substituent selected from halogen atoms, (C1-C7)alkyl,(C6-C30)aryl and nitro groups, or may further include at least onehetero atom selected from O, S and N. Preferably, R⁶¹ and R⁶³independently represent —[CH{(CH₂)₃N⁺Bu₃}₂] or —[CMe{(CH₂)₃N⁺Bu₃}₂], Qin the formula of —CH═N-Q-N═CH— represents trans-1,2-cyclohexylene orethylene, and X(s) independently represent 2,4-dinitrophenolate or BF₄⁻.

According to one embodiment of the complex represented by ChemicalFormula 6, there is provided a complex represented by Chemical Formula7:

wherein

A¹ and A² independently represent an oxygen or sulfur atom;

X(s) independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻, PF₆ ⁻;HCO₃ ⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms;

R⁷² and R⁷⁴ are independently selected from tert-butyl, methyl, ethyl,isopropyl and hydrogen;

R⁷¹ and R⁷³ independently represent —[CH{(CH₂)₃N⁺Bu₃}₂] or—[CMe{(CH₂)₃N⁺Bu₃}₂]; and

b+c represents 5.

According to another embodiment of the complex represented by ChemicalFormula 6, there is provided a complex represented by Chemical Formula8:

wherein

A⁴ represents a carbon or silicon atom;

A¹ and A² independently represent O or S;

X(s) independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻, NO₃ ⁻; PF₆ ⁻;HCO₃ ⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms;

R⁸² and R⁸⁴ are independently selected from tert-butyl, methyl, ethyl,isopropyl and hydrogen;

R⁸¹ and R⁸³ independently represent —[CH{(CH₂)₃N⁺Bu₃}₂] or—[CMe{(CH₂)₃N⁺Bu₃}₂]; R⁸⁵ and R⁸⁶ independently represent (C1-C20)alkyl,(C3-C20)cycloalkyl, (C1-C15)alkyl(C6-C20)aryl or(C6-C20)ar(C1-C15)alkyl; and

b+c represents 5.

According to still another embodiment of the complex represented byChemical Formula 6, there is provided a complex represented by ChemicalFormula 9:

wherein

X(s) independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻;HCO₃ ⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms;

R⁹² and R⁹⁴ are independently selected from methyl, ethyl, isopropyl andhydrogen, preferably methyl;

R⁹¹ and R⁹³ independently represent —[CH{(CH₂)₃N⁺Bu₃}₂] or—[CMe{(CH₂)₃N⁺Bu₃}₂];

Q represents a divalent organic bridge group for linking the twonitrogen atoms;

b+c represents 5; and

the alkyl in the alkylcarboxy anion, alkoxy anion, alkylcarbonate anion,alkylsulfonate anion, alkylamide anion and alkylcarbamate anion may belinear or branched.

Preferably, in the complex represented by Chemical Formula 9, Qrepresents trans-1,2-cyclohexylene or ethylene, and X(s) independentlyrepresent 2,4-dinitrophenolate or BF₄ ⁻. One of the five X radicalsrepresents BF₄ ⁻, two of them represent 2,4-dinitrophenolate, and theremaining two X radicals represent anions represented by ChemicalFormula 10:

wherein

R represents methyl or H.

According to one embodiment of the complex represented by ChemicalFormula 9, there is provided a complex represented by Chemical Formula11:

wherein

B¹ through B⁴ independently represent (C2-C20)alkylene or(C3-C20)cycloalkylene;

R²⁶ represents primary or secondary (C1-C20)alkyl;

R²⁷ through R²⁹ are independently selected from (C1-C20)alkyl and(C6-C30)aryl;

Q represents a divalent bridge group for linking the two nitrogen atoms;

Z¹ through Z⁵ are independently selected from a halide ion; BF₄ ⁻; ClO₄⁻; NO₃ ⁻; PF₆ ⁻; HCO₃ ⁻; and a (C6-C30)aryloxy anion; (C1-C20)carboxylicacid anion; (C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms, wherein a part of Z¹ through Z⁴ coordinated at thecobalt atom may be de-coordinated; and

the alkylene and alkyl may be linear or branched.

Preferably, in, Chemical Formula 11, Q represents (C6-C30)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, wherein thearylene, alkylene, alkenylene, alkynylene, cycloalkylene or fusedcycloalkylene may be further substituted by a substituent selected fromhalogen atoms, (C1-C7)alkyl, (C6-C30)aryl and nitro groups, or mayfurther include at least one hetero atom selected from O, S and N.

Particularly, in Chemical Formula 11, B¹ through B⁴ independentlyrepresent (C2-C6)alkylene, preferably propylene; R²⁶ represents(C1-C7)alkyl; R²⁷ through R²⁹ independently represent (C1-C7)alkyl,preferably R²⁶ and R²⁷ independently represent methyl, and R²⁸ and R²⁹independently represent butyl; Q represents ethylene,trans-1,2-cyclohexylene or 1,2-phenylene, and more preferablytrans-1,2-cyclohexylene; and Z¹ through Z⁵ are independently selectedfrom 2,4-dinitrophenolate and BF₄ ⁻.

According to one embodiment of the complex represented by ChemicalFormula 11, there is provided a complex represented by Chemical Formula12:

wherein

p and q independently represent an integer from 1 to 19;

R²⁶ represents primary or secondary (C1-C20)alkyl;

R²⁷ through R²⁹ are independently selected from (C1-C20)alkyl and(C6-C30)aryl;

Q represents a divalent organic bridge group for linking the twonitrogen atoms; and

Z¹ through Z⁵ are independently selected from a halide ion; BF₄ ⁻; ClO₄⁻; NO₃ ⁻; PF₆ ⁻; HCO₃ ⁻; and a (C6-C30)aryloxy anion; (C1-C20)carboxylicacid anion; (C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms, wherein a part of Z¹ through Z⁴ coordinated at thecobalt atom may be de-coordinated.

Particularly, in Chemical Formula 12, Q represents (C6-C30)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, wherein thearylene, alkylene, alkenylene, alkynylene, cycloalkylene or fusedcycloalkylene may be further substituted by a substituent selected fromhalogen atoms, (C1-C7)alkyl, (C6-C30)aryl and nitro groups, or mayfurther include at least one hetero atom selected from O, S and N.Preferably, Q represents ethylene, trans-1,2-cyclohexylene or1,2-phenylene, and more preferably trans-1,2-cyclohexylene.

Particularly, in Chemical Formula 12, p and q independently represent aninteger from 1 to 5, preferably 2; R²⁶ represents primary or secondary(C1-C7)alkyl; R²⁷ through R²⁹ independently represent (C1-C7)alkyl,preferably R²⁶ and R²⁷ independently represent methyl, and R²⁸ and R²⁹independently represent butyl; and Z¹ through Z⁵ are independentlyselected from 2,4-dinitrophenolate and BF₄ ⁻.

In another aspect, the present invention provides a method for preparingpolycarbonate, including: carrying out copolymerization of carbondioxide and an epoxide compound selected from the group consisting ofC2-C20 alkylene oxide substituted or unsubstituted by halogen or alkoxy;C4-C20 cycloalkene oxide substituted or unsubstituted by halogen oralkoxy; and C8-C20 styrene oxide substituted or unsubstituted byhalogen, alkoxy or alkyl, in the presence of a complex selected from thecomplexes represented by Chemical Formulas 1, 5, 6, 7, 8, 9, 10 and 11and the complexes containing ligands selected from Chemical Formulas 2a,2b, 2c, 3 and 4, as a catalyst.

Cobalt (III) complexes obtained from Salen-type ligands containing fourquaternary ammonium salts may have different structures depending on thestructures of the ligands. Such a different coordination structure isdistinguished from a general structure coordinated with the four ligandsin that it is not coordinated with imine. Instead of imine, the counteranion of the quaternary ammonium salt is coordinated. This has beendemonstrated herein through ¹H, ¹³C, ¹⁵N NMR spectrometry, IRspectrometry, DFT calculation, and cyclic voltammetry (CV). Such adifferent coordination structure is formed when the metal coordinationportion of the Salen ligand is less sterically hindered as a whole, forexample, when the substituent at 3-position of salicylaldehyde as acomponent of the Salen ligand is less sterically hindered (e.g. methyl),and when ethylene diamine as another component of the Salen ligand isnot substituted, or when only one or two hydrogen atoms attached to thefour carbon atoms are substituted (e.g. cyclohexane diamine). On theother hand, when the metal coordination portion of the Salen ligand ishighly sterically hindered as a whole, for example, when a bulkysubstituent, such as tert-butyl, is attached to 3-position ofsalicylaldehyde, or when all of the hydrogen atoms attached to the fourcarbon atoms of ethylene diamine are substituted with methyl groups, aconventionally available imine-coordinated tetradentate compound isobtained.

The following Reaction Scheme illustrates different coordination systemsdepending on the structures of Salen ligands:

R¹ R² *N R 7 H H ¹⁵N H 5 —(CH₂)₄— H 9 —(CH₂)₄— —[(CH₂)₄NBu₃]⁺[BF₄]⁻ 10 —(CH₂)₄— Me

R¹ R² R³ R⁴ *N R R′ 8 H H H H ¹⁵N H ^(t)Bu 6 —(CH₂)₄— H H H ^(t)Bu 11 Me Me Me Me Me Me X = 2,4-dinitrophenolate

The compounds (5, 7 and 10) with a different coordination system havingno coordination with imine unexpectedly show high activity incopolymerizing carbon dioxide/epoxide. On the contrary, the conventionalimine-coordinated tetradentate compounds (6, 8 and 11) have no activityor show low activity. It has been demonstrated through NMR and CVstudies that the conventional imine-coordinated tetradentate compoundsare more easily reduced into cobalt (II) compounds, as compared to thecompounds with a different coordination system having no coordinationwith imine. Such cobalt (II) compounds having no activity in carbondioxide/epoxide copolymerization.

In the compounds with a different coordination system having nocoordination with imine, the anion coordination state is related withthe temperature, solvent and ligand structure. Particularly, the anioncoordination state has been demonstrated through NMR spectrometry inTHF-d₈ similar to the polymerization medium. In the compounds [5, 7 and10 wherein X=2,4-dinitrophenolate (also referred to as DNP)], two DNPligands are always coordinated to cobalt and the remaining two DNPligands continuously undergo conversion/reversion between thecoordinated state and the non-coordinated state. In general, it is knownthat diamagnetic hexa-coordinated cobalt (III) compounds are not activein ligand substitution (Becker, C. A. L.; Motladiile, S. Synth. React.Inorg. Met-Org. Chem. 2001, 31, 1545.). However, in the compounds with adifferent coordination system having no coordination with iminedisclosed herein, cobalt is negatively charged so that negativelycharged ligands may be de-coordinated. The de-coordinated negativelycharged ligands are bound to the cation of the quaternary ammonium salt,and thus may not be released away from cobalt. Basically,non-coordinated anions are thermodynamically unstable species and tendto form coordination bonds back to cobalt. The combination of the abovetwo types of tendencies contributes to the phenomenon in which two DNPligands continuously undergo conversion/reversion between thecoordinated state and the non-coordinated state. Several species oftetra-coordinated cobalt (III) compounds having negatively chargedcobalt have been reported [(a) Collins, T. J.; Richmond, T. G.;Santarsiero, B. D.; Treco B. G. R. T. J. Am. Chem. Soc. 1986, 108, 2088.(b) Gray, H. B.; Billig, E. J. Am. Chem. Soc. 1963, 85, 2019.]. It hasbeen also reported that addition of anionic or neutral ligands to suchcompounds causes easy conversion among the tetra-coordinated system,penta-coordinated system and hexa-coordinated system [(a) Langford, C.H.; Billig, E.; Shupack, S. I.; Gray, H. B. J. Am. Chem. Soc. 1964, 86,2958; (b) Park, J.; Lang, K.; Abboud, K. A.; Hong, S. J. Am. Chem. Soc.2008, 130, 16484.]. It may be stated that such unexpectedly highactivity of the compounds with a different coordination system having nocoordination with imine disclosed herein results from the fact that thetwo anionic ligands continuously undergo conversion/reversion betweenthe coordinated state and the non-coordinated state. The followingReaction Scheme illustrates the mechanism of the growth of a polymerchain in carbon dioxide/epoxide copolymerization. In this mechanism, itis important that the carbonate anion formed at the end of the chainattacks the coordinated epoxide from the rear side. The above-mentionedcontinuous conversion/reversion between the coordinated state and thenon-coordinated state allows a way of attacking the carbonateanion-coordinated epoxide from the rear side. In general, a nucleophilicattack occurs by an attack on a leaving group from the rear side. Thus,it is thought that difference in activities depends on how easily theanion, undergoing continuous conversion/reversion between thecoordinated state and the non-coordinated state, can be de-coordinatedfrom cobalt. According to NMR spectrometric analysis, binding affinitiesof the anions undergoing continuous conversion/reversion between thecoordinated state and the non-coordinated state are in order of 5>10>7.Activities thereof are in reverse order.

In the carbon dioxide/epoxide copolymerization reaction catalyzed withthe compound with a different coordination system having no coordinationwith imine, the ratio of [water]/[catalyst] in the polymerization systemplays an important role in realizing the catalytic activity. Even whenwater is removed by purifying epoxide and carbon dioxide thoroughly, theratio of [water]/[catalyst] may be significantly high under such apolymerization condition that a relatively small amount of catalyst isadded (i.e. under a ratio of [epoxide]/[catalyst] of 100,000 or150,000). To obtain high activity (TON), it is required to realize thepolymerization under a high [epoxide]/[catalyst] ratio, such as 100,000or 150,000. Therefore, it is required for the catalyst to have lowsensitivity to water so as to provide a commercially useful catalyst. Inthe case of a catalyst having a structure of 5, 7 or 10, induction timevaries greatly depending on the degree of dewatering in thepolymerization system. In other words, when the polymerization iscarried out in the dry winter season, it is initiated after about 1-3hours. However, when the polymerization is carried out in the wet andhot summer season, it is initiated sometimes after 12 hours. Once thepolymerization is initiated, similar catalytic activities (TOF) areprovided in the winter and summer seasons. In ¹H NMR spectrometricstudy, it is observed that DNP contained in the compound attackspropylene oxide and the reaction rate rapidly decreases in the presenceof a certain amount of water. It is estimated that such a decrease inthe reaction rate results from the hydrogen bonding of water with theanion that undergoes continuous conversion/reversion between thecoordinated state and the de-coordinated state, followed by degradationof the nucleophilic attacking capability.

Such a great variation in the induction time depending on a degree ofdewatering loads a difficulty on commercialization because of therequirement of optimization in the dewatering degree. When compound 14in the above reaction scheme is used as a catalyst, the above problem ispartially solved. Compound 14 may be obtained under a condition of verylow [propylene oxide]/[catalyst] ratio (1,000 or lower). In this case,the amount of water remaining in propylene oxide is not significantlyhigher than the amount of catalyst. In other words, compound 14 isconsistently obtained by controlling the [water]/[catalyst] ratio at avery low level. Compound 14 may be stored to be used as a catalyst. Inthe case of compound 14, the anion undergoing continuousconversion/reversion between the coordinated state and thede-coordinated state has already been reacted with propylene oxide.Thus, compound 14 has reduced sensitivity to water and thepolymerization is realized under a consistent induction time (1-2hours). In addition, compound 14 shows polymerization activity (TOE,80,000 h⁻¹) in a short induction time (70 minutes) even under a high[epoxide]/[catalyst] ratio of 150,000, and thus provides a higher TON(20,000). In the case of compound 10, it is not capable of realizingpolymerization activity under a [epoxide]/[catalyst] ratio of 150,000.

The compound with a different coordination system having no coordinationwith imine disclosed herein allows production of a compound (e.g.compound 14) having a structure in which the two DNP ligands areconverted into the anions of the Meisenheimer salt by reacting withpropylene oxide. In the case of the compound with a differentcoordination structure having no coordination with imine disclosedherein, two DNP ligands are strongly coordinated to cobalt and theremaining two DNP ligands undergo continuous conversion/reversionbetween the coordinated state and the de-coordinated state. Therefore,the latter two DNP ligands may be reacted rapidly with propylene oxideto provide compound 14 after 1 hour. On the other hand, in the case ofan imine-coordinated tetradentate Salen-Co(III) compound (compound 6, 8or 11), reaction with propylene oxide does not provide a compound (e.g.compound 14), in which only two DNP ligands are converted into theanions of Meisenheimer salt, but causes further conversion of theremaining DNP ligands into the anions of Meisenheimer salt. Especially,during the reaction with propylene oxide, reduction into a cobalt (II)compound may also significantly occur as mentioned above. As a result,it is not possible to obtain a compound (e.g. compound 14), in which twoDNP ligands are maintained and the remaining two DNP ligands areconverted into the anions of Meisenheimer salt. In addition, compound 14may be prepared by the following anion substitution reaction. In theanion substitution reaction, it is a specific feature that one of thesubstituted anions of Meisenheimer salt is converted into DNP. When animine-coordinated tetradentate Salen-Co (III) compound (e.g. compound 6,8 or 11) is subjected to the same anion substitution reaction, cobaltreduction becomes a main reaction.

Particular examples of the epoxide compound that may be used hereininclude ethylene oxide, propylene oxide, butene oxide, pentene oxide,hexene oxide, octene oxide, decene oxide, dodecene oxide, tetradeceneoxide, hexadecene oxide, octadecene oxide, butadiene monoxide,1,2-epoxide-7-octene, epifluorohydrin, epichlorohydrin, epibromohydrin,isopropyl glycidyl ether, butyl glycidyl ether, t-butyl glycidyl ether,2-ethylhexyl glycidyl ether, allyl glycidyl ether, cyclopentene oxide,cyclohexene oxide, cyclooctene oxide, cyclododecene oxide, alpha-pineneoxide, 2,3-epoxide norbornene, limonene oxide, dieldrin,2,3-epoxidepropyl benzene, styrene oxide, phenylpropylene oxide, stilbenoxide, chlorostilben oxide, dichlorostilben oxide,1,2-epoxide-3-phenoxypropane, benzyloxymethyl oxirane,glycidyl-methylphenyl ether, chlorophenyl-2,3-epoxidepropyl-ether,ethoxypropyl methoxyphenyl ether, biphenyl glycidyl ether, glycidylnaphthyl ether, or the like. The epoxide compounds may be used alone orin combination of 2-4 kinds of compounds to perform copolymerizationwith carbon dioxide.

The epoxide compound may be used in the polymerization using an organicsolvent as a reaction medium. Particular examples of the solvent thatmay be used herein include aliphatic hydrocarbons, such as pentane,octane, decane and cyclohexane, aromatic hydrocarbons, such as benzene,toluene and xylene, and halogenated hydrocarbons, such as chloromethane,methylene chloride, chloroform, carbon tetrachloride,1,1-dichloroethane, 1,2-dichloroethane, ethyl chloride, trichloroethane,1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane,1-chloro-2-methylpropane, chlorobenzene and bromobenzene. Such solventsmay be used alone or in combination. More preferably, bulkpolymerization using the monomer itself as a solvent may be performed.

The molar ratio of the epoxide compound to the catalyst, i.e., epoxidecompound:catalyst molar ratio may be 1,000-1,000,000, preferably50,000-200,000. Herein, the catalyst may realize a conversion ratio(i.e., moles of the epoxide compound consumed per mole of cobalt perhour) of 500 turnover/hr or higher. Carbon dioxide may be used at apressure ranging from ambient pressure to 100 atm, preferably from 5 atmto 30 atm. The polymerization temperature may be 20° C.-120° C.,suitably 50° C.-90° C.

To perform polymerization of polycarbonate, batch polymerization,semi-batch polymerization, or continuous polymerization may be used.When using a batch or semi-batch polymerization process, polymerizationmay be performed for 1-24 hours, preferably 1.5-4 hours. A continuouspolymerization process may also be performed for an average catalystretention time of 1.5-4 hours.

According to one embodiment of the present invention, it is possible toobtain polycarbonate having a number average molecular weight (M_(n)) of5,000-1,000,000 and a polydispersity (M_(w)/M_(n)) of 1.05-4.0. Herein,M_(n) means a number average molecular weight as measured by GPC withcalibration using single-molecular weight distribution polystyrenestandards. The polydispersity (M_(w)/M_(n)) means a ratio of a weightaverage molecular weight to a number average molecular weight asmeasured by GPC in the same manner as described above.

The resultant polycarbonate polymer includes at least 80% of carbonatebonds, sometimes at least 95% carbonate bonds. The carbonate material iseasily degradable polymer leaving no residue and soot upon thecombustion, and is useful as a packaging, heat insulating, coatingmaterial, etc.

The present invention provides a method for separately recovering acatalyst from a solution containing a copolymer and the catalyst,including:

contacting a solution containing the copolymer and the catalyst obtainedfrom the above method with a solid inorganic material, polymer materialor a mixture thereof non-soluble in the solution to form a complex ofthe solid inorganic material or polymer material and the catalyst and toseparate the copolymer therefrom; and

treating the complex of the solid inorganic material or polymer materialand the catalyst with an acid or a metal salt of a non-reactive anion ina medium that is not capable of dissolving the solid inorganic materialor polymer material to allow the catalyst to be dissolved into themedium and to separately recover the catalyst.

The expression “solution containing the copolymer and the catalyst” maybe a solution obtained after the polymerization and still containingunreacted carbon dioxide and epoxide, a solution obtained after removingcarbon dioxide only, or a solution obtained after removing both carbondioxide and epoxide and further introducing another solvent thereto forthe post-treatment. Preferred solvents that may be used for thepost-treatment include methylene chloride, THF, etc.

To contact the solution containing the copolymer and the catalyst withthe solid inorganic material, polymer material or a mixture thereof, thesolid inorganic material, polymer material or a mixture thereof may beadded to the solution containing the copolymer and the catalyst,followed by filtration, or the solution containing the copolymer and thecatalyst may be passed through a column packed with the solid inorganicmaterial, polymer material or a mixture thereof. The solid inorganicmaterial may be surface-modified or non-modified silica or alumina. Thesolid polymer material may be a polymer material having a functionalgroup capable of inducing deprotonation by alkoxy anion. Moreparticularly, the functional group capable of inducing deprotonation byalkoxy anion may be a sulfonic acid, carboxylic acid, phenol or alcoholgroup.

The solid polymer material may have a number average molecular weight of500-10,000,000 and is preferably crosslinked. However, non-crosslinkedpolymers may be used as long as they are not dissolved in the solutioncontaining the copolymer and the catalyst. Particular examples of the“solid polymer material having a functional group capable of inducingdeprotonation by alkoxy anion” include a homopolymer or copolymercontaining a constitutional unit represented by any one of ChemicalFormulas 13a to 13e in its polymer chain. Such a polymer materialfunctioning as a support may be non-crosslinked as long as it is notdissolved in the above-mentioned solution. Preferably, the polymermaterial is suitably crosslinked to provide decreased solubility.

The present invention also provides a method for separately recovering acatalyst from a solution containing a copolymer and the catalyst,including:

contacting a solution containing the copolymer and the catalyst obtainedfrom a carbon dioxide/epoxide copolymerization process using the abovecatalyst with silica to form a silica-catalyst complex and to separatethe copolymer therefrom; and

treating the silica-catalyst complex with an acid or a metal salt of anon-reactive anion in a medium that is not capable of dissolving silicato allow the catalyst to be dissolved into the medium and to separatelyrecover the catalyst. The acid may be 2,4-dinitrophenol, and the metalsalt of a non-reactive anion may be MBF₄ (wherein M represents Li, Na orK).

Reaction Scheme 1 shows a mechanism of separation and recovery of thecatalyst. When polymerizing epoxide with carbon dioxide in the presenceof the complex as a catalyst, the anion of the ammonium saltnucleophililically attacks the activated epoxide coordinated to themetal, thereby initiating the polymerization reaction. The alkoxy anionformed by the nucleophilic attack reacts with carbon dioxide to form acarbonate anion, which, in turn, attacks nucleophilically the epoxidecoordinated to the metal to form a carbonate anion. As a result of therepetition of the above process, a polymer chain is formed. In thiscase, the anions of the ammonium salts contained in the catalyst arepartially or totally converted into the carbonate anion or alkoxideanion containing the polymer chain. When removing carbon dioxide afterthe polymerization, the carbonate anions are converted into alkoxideanions. Then, the solution containing the catalyst and the copolymer isallowed to be in contact with the “polymer material having a functionalgroup capable of inducing deprotonation by alkoxy anion” or a solidmaterial (e.g. silica, alumina) having a surface hydroxyl group on thesurface. As a result, the polymer chain receives protons through anacid-base reaction as shown in Reaction Scheme 1 so that it ismaintained in the solution, while the catalyst forms a complex with thesolid inorganic material or polymer material. Since the complex isinsoluble in the solution, it may be easily separated from the solutionvia filtering.

After the separation via filtering, the catalyst may be recovered andrecycled from the complex of the solid inorganic material or polymermaterial with the catalyst. The complex of the solid inorganic materialor polymer material with the catalyst is not dissolved in generalsolvents. However, when the recovered complex is treated with an acid ora metal salt of a non-reactive anion in a medium that is not capable ofdissolving the inorganic material or polymer material, the catalyst maybe dissolved into the medium via an acid-base reaction or saltmetathesis. The resultant mixture may be filtered to allow the catalystto be isolated from the solid inorganic material or polymer material,and then the catalyst may be separated and recovered. Herein, the acidused for the above treatment has a pKa value equal to or lower than thepKa value of the anion formed on the support. Preferably, the acid maybe one whose conjugate base shows excellent activity in thepolymerization in view of the reutilization. Particular examples of suchacids include HCl and 2,4-dinitrophenol. Chloride anions and2,4-dinitrophenolate anions are known to have high activity and highselectivity in the polymerization. Particular examples of the salt of anon-reactive anion include DBF₄ or DClO₄ (wherein D represents Li, Na orK). Upon the treatment with the salt of a non-reactive anion, a compoundcontaining the non-reactive anion is dissolved out. The non-reactiveanion may be replaced by the chloride anion and 2,4-dinitrophenolateanion having high activity and high selectivity via salt metathesis.Recovery of the catalyst may be carried out in a suitable solvent inwhich the catalyst is dissolved but the inorganic material or polymermaterial is not dissolved. Particular examples of such solvents includemethylene chloride, ethanol or methanol.

It is possible to reduce the metal content of the resin to 15 ppm orlower by removing the catalyst through the above method after thepolymerization. Therefore, the present invention also provides acopolymer separated from the solution containing the copolymer and thecatalyst and having a metal content of 15 ppm or lower. If the catalystis not removed from the resin in the above manner, the resin may stillcontain a metal compound that causes coloration. This is not favorableto commercialization. In addition, most transition metals are toxic.Thus, when the metal is not removed from the resin, the resin issignificantly limited in its application. Further, when the polymersolution is not treated in the above manner so that the polymer chainhas no proton at the end thereof, the polymer may be easily convertedinto single molecules via the so-called backbite reaction as shown inReaction Scheme 2, under the condition of a slightly increasedtemperature or long-term storage. This may cause a severe problem whenprocessing the resin and result in a significant degradation in thedurability of the resin. Under these circumstances, the resin is notcommercially acceptable. However, when treating the polymer solution inthe above manner after the polymerizaiton, the polymer chain is providedwith proton at the end thereof, and the alkoxide anion is converted intoan alcohol group, which has weaker nucleophilic reactivity than alkoxideanion. Therefore, the backbite reaction of Reaction Scheme 2 does notoccur so that the resin may provide good processability and durability.

The complex disclosed herein may be prepared by providing an ammoniumsalt-containing ligand and coordinating the ligand to cobalt as shown inReaction Scheme 3. A typical method for attaching the ligand to themetal include reacting cobalt acetate [Co(OAc)₂] with the ligand tode-coordinate the acetate ligand and to remove acetic acid, therebyproviding a cobalt (II) compound, and then oxidizing the cobalt (II)compound with oxygen as an oxidizing agent in the presence of a suitableacid (HX, wherein X is the same as X in Chemical Formula 1) to obtain acobalt (III) compound. The ammonium salt-containing ligand may beprepared according to the known method developed by the presentinventors (J. Am. Chem. Soc. 2007, 129, 8082; Angew. Chem. Int. Ed.,2008, 47, 7306-7309).

Advantageous Effects

The complex disclosed herein is prepared from a ligand containing aprotonated group so that it takes a negative divalently or highervalently charged form. The complex may be used in carbon dioxide/epoxidecopolymerization as a catalyst to realize high activity and highselectivity consistently. In addition, when carrying out carbondioxide/epoxide copolymerization using the complex disclosed herein as acatalyst, the catalyst having protonated ligands is separated andrecovered after the copolymerization so that it may be recycled. In thismanner, it is possible to reduce the cost required for the catalyst andto realize high cost efficiency when preparing the copolymer. It is alsopossible to obtain a high-purity copolymer by removing the catalyst,i.e., metal compound from the copolymer. Therefore, it is possible toextend applications of the copolymer and to enhance the durability andprocessability of the copolymer.

DESCRIPTION OF DRAWINGS

The above and other objects, features and advantages of the presentinvention will become apparent from the following description ofpreferred embodiments given in conjunction with the accompanyingdrawings, in which:

FIG. 1 shows ¹H NMR spectra of compounds 7 and 8 in DMSO-d₆ as asolvent, wherein the signals labeled with X correspond to DNP signalsand the 2D spectrum in the box is ¹H-¹H COSY NMR spectrum of compound 7at 20° T.

FIG. 2 shows ¹³C NMR spectra of compounds 7 and 8 in DMSO-d₆ as asolvent.

FIG. 3 shows ¹⁵N NMR spectra of compounds 7 and 8 in DMSO-d₅ as asolvent.

FIG. 4 shows ¹H NMR spectra of compounds 7 and 8 in THF-d₈ and CD₂Cl₂ asa solvent.

FIG. 5 shows IR spectra of compounds 7 and 8.

FIG. 6 shows the most stable conformation of compound 7 obtained by DFTcalculation, wherein only the oxygen atoms of DNP ligands coordinated tothe metal are shown for the purpose of simplicity.

FIG. 7 is a reaction scheme illustrating a change in the state of DNP atroom temperature depending on the solvent, in the case of a compoundwith a different coordination system having no coordination with imine(X=DNP).

FIG. 8 shows VT ¹H NMR spectrum of compound 7 in THF-d₈.

FIG. 9 is ¹H NMR spectrum illustrating the reaction between compound 10or 8 and propylene oxide, wherein the signals marked with “*” correspondto new signals derived from the anion of Meisenheimer salt.

BEST MODE

Hereinafter, the embodiments of the present invention will be describedin detail with reference to examples. However, the following examplesare for illustrative purposes only and not intended to limit the scopeof this disclosure.

Example 1 Preparation of 3-methyl-5-[{BF₄⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde Compound

The title compound is prepared by hydrolyzing the ligand represented byChemical Formula 19a. The compound represented by Chemical Formula 19ais obtained by the known method developed by the present inventors(Angew. Chem. Int. Ed., 2008, 47, 7306-7309).

The compound represented by Chemical Formula 19a (0.500 g, 0.279 mmol)was dissolved in methylene chloride (4 mL), and then aqueous HI solution(2N, 2.5 mL) was added thereto and the resultant mixture was agitatedfor 3 hours at 70° C. The aqueous layer was removed, the methylenechloride layer was washed with water and dried with anhydrous magnesiumchloride, and the solvents were removed under reduced pressure. Theresultant product was purified by silica gel column chromatographyeluting with methylene chloride/ethanol (10:1) to obtain 0.462 g of3-methyl-5-[{I⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde (yield 95%). Thecompound was dissolved in ethanol (6 mL), and AgBF₄ (0.225 g, 1.16 mmol)was added thereto, and the resultant mixture was stirred for 1.5 hoursat room temperature, followed by filteration. The solvents were removedunder reduced pressure and the resultant product was purified by silicagel column chromatography eluting with methylene chloride/ethanol (10:1)to obtain 0.410 g of 3-methyl-5-[{BF₄ ⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehydecompound (yield 100%).

¹H NMR (CDCl₃): δ 11.19 (s, 1H, OH), 9.89 (s, 1H, CHO), 7.48 (s, 1H,m-H), 7.29 (s, 1H, m-H), 3.32-3.26 (m, 4H, —NCH₂), 3.10-3.06 (m, 12H,—NCH₂), 2.77 (septet, J=6.8 Hz, 1H, —CH—), 2.24 (s, 3H, —CH₃), 1.76-1.64(m, 8H, —CH₂), 1.58-1.44 (m, 16H, —CH₂), 1.34-1.29 (m, 8H, —CH₂), 0.90(t, J=7.6 Hz, 18H, CH₃) ppm. ¹³C NMR (CDCl₃): δ 197.29, 158.40, 136.63,133.48, 130.51, 127.12, 119.74, 58.23, 40.91, 32.51, 23.58, 19.48,18.82, 15.10, 13.45 ppm.

Example 2 Preparation of 3-t-butyl-5-[{BF₄⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde Compound

The title compound is prepared from the compound represented by Chemical

Formula 19b in the same manner as described in Example 1. The compoundrepresented by Chemical Formula 19a is also obtained by the known methoddeveloped by the present inventors (Angew. Chem. Int. Ed., 2008, 47,7306-7309).

¹H NMR (CDCl₃): δ 11.76 (s, 1H, OH), 9.92 (s, 1H, CHO), 7.53 (s, 1H,m-H), 7.35 (s, 1H, m-H), 3.36-3.22 (m, 16H, —NCH₂), 2.82 (br, 1H, —CH—),1.78-1.70 (m, 4H, —CH₂), 1.66-1.46 (m, 16H, —CH₂), 1.42 (s, 9H,—C(CH₃)₃), 1.38-1.32 (m, 12H, butyl —CH₂), 0.93 (t, J=7.6 Hz, 18H, CH₃)ppm. ¹³C {¹H} NMR (CDCl₃): δ 197.76, 159.67, 138.70, 133.50, 132.63,131.10, 120.40, 58.55, 41.45, 34.99, 32.28, 29.31, 23.72, 19.59, 19.00,13.54 ppm.

Example 3 Preparation of Complex 7

Reaction Scheme 4 schematically illustrates one embodiment of the methodfor preparing the complex disclosed herein.

Ethylene diamine dihydrochloride (10 mg, 0.074 mmol), sodium t-butoxide(14 mg) and 3-methyl-5-[{BF₄ ⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde compound(115 mg) obtained from Example 1 are weighed with vials in a dry box,and ethanol (2 mL) was added thereto, followed by stirring at roomtemperature for overnight. The reaction mixture was filtered and solventwere removed under reduced pressure. The resultant product wasredissolved into methylene chloride and filtered once again. Thesolvents were removed under reduced pressure, and Co(OAc)₂ (13 mg, 0.074mmol) and ethanol (2 mL) are added thereto. The reaction mixture wasstirred for 3 hours at room temperature and then the solvents wereremoved under reduced pressure. The resultant compound was washed withdiethyl ether (2 mL) twice to obtain a solid compound. The solidcompound was dissolved into methylene chloride (2 mL) and2,4-dinitrophenol (14 mg, 0.074 mmol) was added thereto, and theresultant mixture was stirred for 3 hours in the presence of oxygen.Then, sodium 2,4-dinitrophenolate (92 mg, 0.44 mmol) was added to thereaction mixture and the stirring continued for overnight at roomtemperature. The reaction mixture was filtered over a pad of Celite andthe solvents were removed to obtain the product as a dark brown solidcompound (149 mg, yield 100%).

¹H NMR (DMSO-d₆, 40° C.): δ 8.84 (br, 2H, (NO₂)₂C₆H₃O), 8.09 (br, 2H,(NO₂)₂C₆H₃O), 8.04 (s, 1H, CH═N), 7.12 (s, 2H, m-H), 6.66 (br, 2H,(NO₂)₂C₆H₃O), 4.21 (br, 2H, ethylene-CH₂), 3.35-2.90 (br, 16H, NCH₂),2.62 (s, 3H, CH₃), 1.91 (s, 1H, CH), 1.68-1.42 (br, 20H, CH₂), 1.19 (br,12H, CH₂), 0.83 (br, 18H, CH₃) ppm. ¹H NMR (THF-d₈,20° C.): δ 8.59 (br,1H, (NO₂)₂C₆H₃O), 8.10 (br, 1H, (NO₂)₂C₆H₃O), 7.93 (s, 1H, CH═N), 7.88(br, 1H, (NO₂)₂C₆H₃O), 7.05 (s, 1H, m-H), 6.90 (s, 1H, m-H), 4.51 (s,2H, ethylene-CH₂), 3.20-2.90 (br, 16H, NCH₂), 2.69 (s, 3H, CH₃), 1.73(s, 1H, CH), 1.68-1.38 (br, 20H, CH₂), 1.21 (m, 12H, CH₂), 0.84 (t,J=6.8 Hz, 18H, CH₃) ppm. ¹H NMR (CD₂Cl₂, 20° C.): δ 8.43 (br, 1H,(NO₂)₂C₆H₃O), 8.15 (br, 1H, (NO₂)₂C₆H₃O), 7.92 (br, 1H, (NO₂)₂C₆H₃O),7.79 (s, 1H, CH═N), 6.87 (s, 1H, m-H), 6.86 (s, 1H, m-H), 4.45 (s, 2H,ethylene-CH₂), 3.26 (br, 2H, NCH₂), 3.0-2.86 (br, 14H, NCH₂), 2.65 (s,3H, CH₃), 2.49 (br, 1H, CH), 1.61-1.32 (br, 20H, CH₂), 1.31-1.18 (m,12H, CH₂), 0.86 (t, J=6.8 Hz, 18H, CH₃) ppm. ¹³C{¹H} NMR (DMSO-d₆, 40°C.): δ 170.33, 165.12, 160.61, 132.12 (br), 129.70, 128.97, 127.68 (br),124.51 (br), 116.18 (br), 56.46, 40.85, 31.76, 21.92, 18.04, 16.16,12.22 ppm. ¹⁵N{¹H} NMR (DMSO-d₆, 20° C.): δ −156.32, −159.21 ppm.¹⁵N{¹H} NMR (THF-d₈, 20° C.): δ −154.19 ppm. ¹⁹F{¹H} NMR (DMSO-d₆, 20°C.): δ −50.63, −50.69 ppm.

Example 4 Preparation of Complex 8

Complex 8 is prepared from 3-t-butyl-5-[{BF₄⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde obtained from Example 2 in the samemanner as described in Example 3.

¹H NMR (DMSO-d₆, 40° C.): δ 8.82 (br, 2H, (NO₂)₂C₆H₃O), 7.89 (br, 3H,(NO₂)₂C₆H₃O, CH═N), 7.21 (s, 1H, m-H), 7.19 (s, 1H, m-H), 6.46 (br, 4H,(NO₂)₂C₆H₃O), 4.12 (s, 2H, ethylene-CH₂), 3.25-2.96 (br, 16H, NCH₂),1.90 (s, 1H, CH), 1.71 (s, 9H, C(CH₃)₃), 1.67-1.32 (br, 20H, CH₂),1.32-1.15 (m, 12H, CH₂), 0.88 (t, J=7.2 Hz, 18H, CH₃) ppm. ¹H NMR(THF-d₈, 20° C.): δ 7.78 (s, 1H, CH═N), 7.31 (s, 1H, m-H), 7.12 (s, 1H,m-H), 4.19 (br, 2H, ethylene-CH₂), 3.43-2.95 (br, 16H, NCH₂), 2.48 (br,1H, CH), 1.81-1.52 (br, 20H, CH₂), 1.50 (s, 9H, C(CH₃)₃), 1.42-1.15 (br,12H, CH₂), 0.89 (t, J=6.8 Hz, 18H, CH₃) ppm. ¹H NMR (CD₂Cl₂, 20° C.): δ7.47 (s, 1H, CH═N), 7.10 (s, 1H, m-H), 7.07 (s, 1H, m-H), 4.24 (s, 2H,ethylene-CH₂), 3.31 (br, 2H, NCH₂), 3.09-2.95 (br, 14H, NCH₂), 2.64 (br,1H, CH), 1.68-1.50 (br, 20H, CH₂), 1.49 (s, 9H, C(CH₃)₃), 1.39-1.26 (m,12H, CH₂), 0.93 (t, J=6.8 Hz, 18H, CH₃) ppm. ¹³C{¹H} NMR (DMSO-d₆, 40°C.): δ 166.57, 166.46, 161.55, 142.16, 129.99, 129.26, 128.39, 128.13,127.63, 124.18, 118.34, 56.93, 41.64, 34.88, 32.27, 29.63, 22.37, 18.64,18.51, 12.70 ppm. ¹⁵N{¹H} NMR (DMSO-d₆): −163.43 ppm. ¹⁵N{¹H} NMR(THF-d₈, 20° C.): δ −166.80 ppm. ¹⁹F{¹H} NMR (DMSO-d₆, 20° C.): δ−50.65, −50.70 ppm.

Example 5 Preparation of Complex 9

Complex 9 is prepared according to Reaction scheme 5.

Preparation of Compound 17

First, 1-chloro-4-iodobutane (1.00 g, 4.57 mmol) was dissolved into amixture solvent of diethyl ether/pentane (2:3) to obtain a concentrationof 0.10 M, the resultant mixture was cooled to −78° C. t-butyl lithium(3.690 g, 9.610 mmol, 1.7M solution in pentane) was added gradually tothe cooled solution of 1-chloro-4-iodobutane and stirred for 2 hours.1,5-dichloropentane-3-one (838 mg, 4.580 mmol) dissolved in diethylether (8 mL) was added gradually to the reaction mixture. The reactionmixture was stirred for additional 4 hours at −78° C., and then icewater (50 mL) was added to quench the reaction path, followed byextraction with diethyl ether. The organic layer was collected and driedover anhydrous magnesium sulfate and filtered, the solvents were removedunder reduced pressure. The obtained crude product was purified bycolumn chromatography using silica gel (hexane:ethyl acetate=5:1) toobtain 820 mg of compound 17 (yield 65%).

¹H NMR (CDCl₃): δ 3.52 (t, J=6.4 Hz, 6H, CH₂Cl), 1.80-1.73 (m, 6H, CH₂),1.56-1.52 (m, 4H, CH₂), 1.42 (s, 4H, CH₂) ppm. ¹³C{¹H} NMR (CDCl₃): δ73.58, 45.69, 44.95, 38.29, 36.48, 32.94, 26.96, 20.88 ppm.

Preparation of Compound 18

Under nitrogen atmosphere, compound 17 (1.122 g, 4.070 mmol), o-cresol(3.521 g, 32.56 mmol), and aluminum trichloride (0.597 g, 4.477 mmol)were added to a round bottom flask and stirred for overnight. Diethylether (20 mL) and water (20 mL) were added thereto the reaction flask,and the aqueous phase was repeatedly extracted with diethyl ether (threetimes). The organic phases are combined and dried over anhydrousmagnesium sulfate, filtered and removed the solvents under reducedpressure. The resultant oily product was purified by columnchromatography using silica gel (hexane:ethyl acetate=10:1) to obtain907 mg of compound 18 (yield 61%).

IR (KBr): 3535 (OH) cm⁻¹. ¹H NMR (CDCl₃): δ7.02 (d, J=2.0 Hz, 1H, m-H),6.99 (dd, J=8.8 Hz, 2.0 Hz, 1H, m-H), 6.73 (d, J=8.0 Hz, 1H, o-H), 4.67(s, 1H, OH), 3.53-3.46 (m, 6H, CH₂Cl), 2.27 (s, 3H, CH₃), 1.79-1.44 (m,6H, CH₂), 1.67-1.62 (m, 2H, CH₂), 1.58-1.53 (m, 4H, CH₂), 1.28-1.20 (br,2H, CH₂) ppm. ¹³C{¹H} NMR (CDCl₃): δ 151.81, 137.96, 128.89, 124.87,114.70, 60.83, 46.05, 45.04, 42.09, 36.69, 35.07, 27.26, 21.40, 21.02,16.54, 14.49 ppm. HRMS (FAB): m/z calcd (M⁺C₁₈H₂₇Cl₃O) 364.1131. found365.1206

Preparation of Compound 19

Compound 18 (907 mg, 2.48 mmol), paraformaldehyde (298 mg, 9.920 mmol),magnesium dichloride (944 mg, 9.92 mmol) and triethylamine (1.051 g,10.42 mmol) were introduced into a flask, and tetrahydrofuran (50 mL)was added as the solvent. The reaction mixture was refluxed for 5 hoursunder nitrogen atmosphere. The reaction mixture was cooled to roomtemperature, and methylene chloride (50 mL) and water (50 mL) were addedthereto to extract the organic layer. The organic layer was collectedand dried over anhydrous magnesium sulfate, filtered and removed thesolvents. The resultant product was purified by column chromatographyusing silica gel (hexane:ethyl acetate=20:1) to obtain 540 mg ofcompound 19 (yield 58%).

IR (KBr): 2947 (OH), 1650 (C═O) cm⁻¹. ¹H NMR (CDCl₃): δ 11.05 (s, 1H,OH), 9.78 (s, 1H, CH═O), 7.25 (s. 1H, m-H), 7.19 (s, 1H, m-H), 3.44-3.39(m, 6H, CH₂Cl), 2.19 (s, 3H, CH₃), 1.74-1.43 (m, 12H, CH₂), 1.20-1.11(br, 2H, CH₂) ppm. ¹³C{¹H} NMR (CDCl₃): δ 196.79, 158.07, 136.98,135.85, 128.95, 126.85, 119.52, 45.77, 44.88, 42.12, 36.50, 34.64,33.09, 27.07, 20.85, 15.71 ppm. HRMS (FAB): m/z calcd (M⁺C₁₉H₂₇Cl₃O)393.1151. found 393.1155

Preparation of Compound 20

Compound 19 (520 mg, 1.304 mol) and sodium iodide (2.932 g, 19.56 mmol)were introduced into a flask, and acetonitrile (2 mL) was added as thesolvent, followed by refluxing for 12 hours. Then, the solvent isremoved under reduced pressure, methylene chloride (5 mL) and water (5mL) are added thereto to extract the organic layer. The organic layer isdried over anhydrous magnesium sulfate and the solvent is removed underreduced pressure. The resultant product is purified through a column(hexane:ethyl acetate=20:1) to obtain 759 mg of compound 20 (yield 87%).

IR (KBr): 2936 (OH), 1648 (C═O) cm⁻¹. ¹H NMR (CDCl₃): δ 11.06 (s, 1H,OH), 9.80 (s, 1H, CH═O), 7.25 (s. 1H, m-H), 7.17 (d, J=2.8 Hz, 1H, m-H),3.21-3.14 (m, 6H, CH₂Cl), 2.27 (s, 3H, CH₃), 1.79-1.53 (m, 121-1, CH₂),1.28-1.19 (br, 2H, CH₂) ppm. ¹³C{¹H} NMR (CDCl₃): δ 196.81, 158.20,137.00, 135.90, 128.90, 126.98, 119.54, 42.17, 38.45, 36.11, 33.93,27.83, 24.50, 15.84, 7.96, 7.14 ppm.

Preparation of Compound 21

Compound 20 (680 mg, 1.018 mmol) and cyclohexyl diamine (58 mg, 0.509mmol) were dissolved in methylene chloride (5 mL) and the reactionmixture was stirred for 12 hours. The resultant product was purified bypassing through a short pad of silica eluting with methylene chloride toobtain the product as a pure yellow solid (560 mg, yield 78%).

IR (KBr): 2933 (OH), 1629 (C═N) cm⁻¹. ¹H NMR (CDCl₃): δ 13.45 (s, 2H,OH), 8.34 (s, 2H, CH═N), 7.05 (s, 2H, m-H), 6.941 (d, J=1.6 Hz, 2H,m-H), 3.39-3.36 (m, 2H, cyclohexyl-CH), 3.17-3.09 (m, 12H, CH₂I), 2.26(s, 6H, CH₃), 1.96-1.89 (m, 4H, cyclohexyl-CH₂), 0.96-1.43 (m, 32H,cyclohexyl-CH₂ and CH₂), 1.18-1.20 (br, 4H, CH₂) ppm. ¹³C{¹H} NMR(CDCl₃): δ 164.97, 157.2, 135.58, 131.25, 127.12, 125.50, 117.65, 72.89,42.00, 38.71, 36.14, 34.18, 33.73, 27.91, 24.57, 24.50, 16.32, 8.26,7.18 ppm.

Preparation of Compound 22

Compound 21 (364 mg, 0.257 mmol) was dissolved in acetonitrile (5 mL),and added tributylamine (291 mg, 1.57 mmol). The reaction mixture wasreflux for 2 days under nitrogen atmosphere. The reaction mixture wascooled to room temperature, the solvents were removed under reducedpressure, and diethyl ether (10 mL) was added. The resultant slurry wasstirred for 10 minutes to obtain the product in solid form. Diethylether was decanted and the above process was repeated twice. The yellowsolid was collected by filtration followed by washing with diethylether. The residual solvents were completely by applying vacuum toobtain 579 mg of compound 22 (yield 89%).

IR (KBr): 2959 (OH), 1627 (C═N) cm⁻¹. ¹H NMR (CDCl₃): δ. 13.46 (s, 2H,OH), 8.58 (s, 2H, CH═N), 7.18 (s, 2H, m-H), 7.07 (s, 2H, m-H), 3.42 (br,2H, cyclohexyl-CH), 3.32 (br, 16H, NCH₂), 3.16 (br, 32H, NCH₂), 2.10 (s,6H, CH₃), 1.74-1.20 (br, 108H, cyclohexyl-CH₂, CH₂), 0.86 (t, 18H, CH₃),0.75 (t, 36H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ164.78, 157.27, 134.04,130.82, 127.22, 125.15, 117.46, 71.01, 9.96, 59.63, 59.00, 58.86, 53.52,43.03, 34.89, 33.90, 33.68, 24.16, 24.05, 23.07, 22.78, 20.69, 19.68,19.53, 17.64, 15.79, 13.58 ppm.

Preparation of Compound 23

Compound 22 (455 mg, 0.180 mmol) and silver tetrafluoro borate (211 mg,1.08 mmol) were introduced into a flask, and methylene chloride (12 mL)is added as a solvent. The flask was wrapped with aluminum foil and thereaction mixture was stirred at room temperature for 1 day. The reactionmixture was filtered over a pad of celite to remove solid, and theremaining solution was removed under reduced pressure. The product waspurified by column chromatography using silica gel (methylenechloride:ethanol=5:1) to obtain 322 mg of yellow compound 23 (yield78%).

IR (KBr): 2961 (OH), 1628 (C═N) cm⁻¹. ¹H NMR (CDCl₃): δ. 13.64 (s, 2H,OH), 8.52 (s, 2H, CH═N), 7.27 (s, 2H, m-H), 7.16 (s, 2H, m-H), 3.44 (br,2H, cyclohexyl-CH), 3.30-3.10 (br, 48H, NCH₂), 2.24 (s, 6H, CH₃),1.95-1.29 (br, 108H, cyclohexyl-CH₂, CH₂), 0.99 (t, 18H, CH₃), 0.90 (t,36H, CH₃) ppm.

Preparation of Complex 9

Compound 23 (59 mg, 0.026 mmol) and Co(OAc)₂ (4.6 mg, 0.026 mmol) wereintroduced into a vial in a glove box, ethanol (1 mL) was added and thereaction mixture was stirred for 12 hours. The solvent was removed underreduced pressure and the resultant product was washed twice with diethylether to obtain a red solid. 2,4-dinitrophenol (5.0 mg, 0.026 mmol) wasadded to and the reaction mixture and stirred for 3 hours in thepresence of oxygen atmosphere. sodium 2,4-dinitrophenolate (27 mg, 0.13mmol) was added to the reaction flask and stirred for further 12 hours.The resultant solution was filtered over a pad of celite, removed thesolvents under reduced pressure to obtain 73 mg of a dark red solid.

IR (KBr): 2961 (OH), 1607 (C═N) cm⁻¹. ¹H NMR (DMSO-d₆, 38° C.): δ 8.68(br, 4H, (NO₂)₂C₆H₃O), δ. 8.05 (br, 4H, (NO₂)₂C₆H₃O), 7.85 (br, 2H,CH═N), 7.30 (br, 4H, m-H), 6.76 (br, 4H, (NO₂)₂C₆H₃O), 3.58 (br, 2H,cyclohexyl-CH), 3.09 (br, 48H, NCH₂), 2.63 (s, 6H, CH₃), 1.53-1.06 (br,108H, cyclohexyl-CH₂, CH₂), 0.93-0.85 (m, 54H, CH₃) ppm.

Example 6 Preparation of Complex 10

Complex 10 is prepared according to Reaction Scheme 6.

Preparation of Compound 24

First, 1,7-dichloroheptan-4-one (17.40 g, 95.04 mmol) was dissolved intodiethyl ether (285 mL) under nitrogen atmosphere. The reaction mixturewas cooled to −78° C., MeLi (1.5 M solution in diethyl ether 80.97 g,142.56 mmol) was added drop wise using a syringe under nitrogenatmosphere. The reaction mixture was stirred for 2 hours at −78° C.water (170 mL) was added at −78° C. to quench the reaction. The productwas extracted using diethyl ether. The aqueous layer was repeatedlyextracted with diethyl ether (2 times). Collected the organic phases anddried over anhydrous magnesium sulfate, followed by filtration and thesolvents were removed under reduced pressure to obtain 17.99 g ofcompound 24 (yield 95%). The resultant product may be used directly forthe subsequent reaction without further purification.

¹H NMR (CDCl₃): δ. 3.59 (t, J=6.4 Hz, 4H, CH₂Cl), 1.90-1.86 (m, 4H,CH₂), 1.64-1.60 (m, 4H, CH₂), 1.23 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR(CDCl₃): δ. 72.32, 45.88, 39.51, 27.60, 27.23 ppm.

Preparation of Compound 25

Under nitrogen atmosphere, o-cresol (78.17 g, 722.82 mmol), compound 24(17.99 g, 90.35 mmol) and AlCl₃ (13.25 g, 99.39 mmol) were mixed in around bottom flask and stirred overnight. Diethyl ether (500 mL) andwater (300 mL) were added to quench the reaction. The organic layer wascollected and the aqueous layer was further extracted three times withdiethyl ether (300 mL) and collected the organic layer. The organiclayer was dried over anhydrous magnesium sulfate, followed byfiltration, and then the solvent were removed by a rotary evaporatorunder reduced pressure. The excess o-cresol was removed by vacuumdistillation (2 mm Hg) at 85° C. The obtained product can be used forsubsequent reaction without further purification. In this manner, 25.40g of compound 25 was obtained (yield 97%).

¹H NMR (CDCl₃): δ. 7.01 (d, J=2.0 Hz, 1H, m-H), 6.97 (dd, J=8.0 Hz, 2.0Hz, 1H, m-H), 6.72 (d, J=8.0 Hz, 1H, o-H), 4.85 (s, 1H, OH), 3.45 (t,J=6.4 Hz, 4H, CH₂Cl), 2.27 (s, 3H, CH₃), 1.86-1.44 (m, 8H, CH₂), 1.30(s, 3H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 151.79, 138.67, 129.06,125.02, 123.45, 114.85, 46.20, 41.12, 39.95, 28.09, 24.22, 16.58 ppm.

Preparation of Compound 26

Compound 25 (25.40 g, 87.83 mmol) was dissolved in tetrahydrofuran (650mL) under nitrogen atmosphere. Paraformaldehyde (10.55 g, 351.32 mmol),magnesium chloride (33.52 g, 351.32 mmol) and triethylamine (37.31 g,368.89 mmol) were introduced, into a flask under nitrogen atmosphere,and a refluxed for 5 hours under nitrogen atmosphere. The solvent wasremoved by a rotary evaporator under reduced pressure and methylenechloride (500 mL) and water (300 mL) were added. The resultant mixturewas filtered over a pad of Celite to obtain a methylene chloride layer.The aqueous layer was further extracted three times with methylenechloride (300 mL) and combined organic layers, dried over anhydrousmagnesium sulfate and filtered, the solvents were removed by a rotaryevaporator under reduced pressure to obtain an oily compound. Theremaining trace amount of triethylamine is removed by a vacuum pump. Theresultant compound has high purity as determined by NMR analysis and canbe used for the subsequent reaction without further purification. Inthis manner, 26.75 g of compound 26 was obtained (yield 96%).

¹H NMR (CDCl₃): δ. 11.14 (s, 1H, OH), 9.87 (s, 1H, CH═O), 7.33 (d, J=2.4Hz, 1H, m-H), 7.26 (d, J=2.4 Hz, 1H, m-H), 3.47 (t, J=6.4 Hz, 4H,CH₂Cl), 2.30 (s, 3H, CH₃), 1.90-1.40 (m, 8H, CH₂), 1.35 (s, 3H, CH₃)ppm. ¹³C{¹H} NMR (CDCl₃): δ. 196.87, 158.22, 137.56, 136.11, 128.91,119.69, 45.88, 40.67, 39.98, 27.96, 24.06, 15.81 ppm.

Preparation of Compound 27

Compound 26 (26.75 g, 84.32 mmol) was dissolved in acetonitrile (107mL). Sodium iodide (126.39 g, 843.18 mmol) was added and the resultingmixture was refluxed for overnight. After cooling the reaction mixtureto room temperature, water (300 mL) was added. The resultant solutionwas extracted three times with diethyl ether (300 mL) to collect theorganic layer. The organic layer was dried over anhydrous magnesiumsulfate, followed by filtration; the solvents were removed by a rotaryevaporator under reduced pressure. The resultant product was purifiedthrough silica gel column chromatography eluting with hexane-toluene(5:1) as eluent to obtain the compound 27 (22.17 g, yield 83%).

¹H NMR (CDCl₃): δ. 11.14 (s, 1H, OH), 9.87 (s, 1H, CH═O), 7.33 (d, J=2.4Hz, 1H, m-H), 7.25 (d, J=2.4 Hz, 1H, m-H), 3.14-3.09 (m, 4H, CH₂I), 2.30(s, 3H, CH₃), 1.87-1.43 (m, 8H, CH₂), 1.34 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR(CDCl₃): δ. 196.85, 158.20, 137.50, 136.09, 128.85, 126.93, 119.62,44.28, 39.95, 28.66, 24.16, 15.81, 7.99 ppm.

Preparation of Compound 28

Compound 27 (8.56 g, 17.01 mmol) was dissolved in methylene chloride (97mL) under nitrogen atmosphere. (±)-trans-1,2-diaminocyclohexane (0.97 g,8.50 mmol) was added and stirred for overnight. Solvents were removedunder reduced pressure to obtain the pure compound (9.00 g, yield 98%).

¹H NMR (CDCl₃): δ. 13.48 (s, 1H, OH), 8.31 (s, 1H, CH═N), 7.04 (d, J=1.6Hz, 1H, m-H), 6.91 (d, J=1.6 Hz, 1H, m-H), 3.38-3.35 (m, 1H,cyclohexyl-CH), 3.08-3.03 (m, 4H, CH₂I), 2.25 (s, 3H, CH₃), 1.96-1.89(m, 2H, cyclohexyl-CH₂), 1.96-1.43 (m, 10H, cyclohexyl-CH₂ and CH₂),1.26 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 165.01, 157.31, 136.12,131.35, 126.93, 125.54, 117.67, 72.94, 44.47, 39.79, 33.73, 28.72,24.57, 24.32, 16.28, 8.38, 8.26 ppm.

Preparation of Compound 29

Compound 28 (0.855 g, 0.79 mmol) was dissolved in acetonitrile (8.5 mL)under nitrogen atmosphere, tributyl amine (1.17 g, 6.32 mmol) was addedand the resulting solution was refluxed for 48 hours. Solvents wereremoved by a rotary evaporator under reduced pressure. Diethyl ether (20mL) was added to the obtained slurry and titurated for 15 minutes toprecipitate the product as solid. The ether layer was decanted and theabove process was repeated twice to obtain beige solid compound. Thesolid compound was added gradually to solution of AgBF₄ (0.642 g, 3.30mmol) in ethanol (40 mL) with stirring. The reaction mixture wasagitated for 24 hours under light-shielded atmosphere, and the resultantAgI was removed by filteration over a pad of celite. The solvents wereremoved under vacuum. Then, the resultant compound was dissolved inmethylene chloride (6 mL), and further filtered through a Celite pad toremove floating materials. The resultant product was purified by columnchromatography using silica, eluting with methylene chloride-ethanol(5:1) as eluent to obtain the purified compound (1.23 g, yield 90%).

¹H NMR (CDCl₃): δ. 13.55 (s, 1H, OH), 8.42 (s, 1H, CH═N), 7.12 (s, 1H,m-H), 7.08 (s, 1H, m-H), 3.38 (br, 1H, cyclohexyl-CH), 3.06 (br, 16H,NCH₂), 2.20 (s, 3H, CH₃), 1.88-1.84 (br, 2H, cyclohexyl-CH₂), 1.68-1.26(br, 36H), 0.87-0.86 (br, 18H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 165.23,157.79, 135.21, 131.17, 127.18, 125.76, 117.91, 72.05, 59.16, 58.63,40.16, 38.10, 37.71, 26.45, 24.91, 23.90, 20.31, 19.80, 17.30, 16.01,13.97, 13.80, 13.79 ppm.

Preparation of Complex 10

Compound 29 (100 mg, 0.06 mmol) and Co(OAc)₂ (10.7 mg, 0.06 mmol) wereintroduced into a flask and ethanol (3 mL) was added as the solvent. Thereaction mixture was stirred at room temperature for 3 hours and removedthe solvents under reduced pressure. The obtained product was triturated2 times with diethyl ether to obtain the red solid compound. Theresidual solvents were removed completely by applying reduced pressure.Methylene chloride (3 mL) was added to dissolve the compound. Then,2,4-dinitrophenol (11.1 mg, 0.06 mmol) was introduced and the reactionmixture was stirred for 3 hours under oxygen atmosphere. Under oxygenatmosphere, sodium-2,4-dinitrophenolate (74.5 mg, 0.30 mmol) wasintroduced and the mixture was stirred for overnight. The resultantsolution was filtered over a pad of celite and the solvents were removedunder reduced pressure to obtain the complex 10 (137 mg, yield 100%).

¹H NMR (DMSO-d₆,38° C.): δ. 8.65 (br, 2H, (NO₂)₂C₆H₃O), δ. 7.88 (br, 3H,(NO₂)₂C₆H₃O, CH═N), 7.31 (br, 2H, m-H), 6.39 (br, 2H, (NO₂)₂C₆H₃O), 3.38(br, 1H, cyclohexyl-CH), 3.08 (br, 16H, NCH₂), 2.64 (s, 3H, CH₃),2.06-1.85 (br, 2H, cyclohexyl-CH₂), 1.50-1.15 (br, 36H), 0.86 (br, 18H,CH₃) ppm.

Example 7 Preparation of Complex 11

3-methyl-5-[{BF₄ ⁻Bu₃N⁺(CH₂)₃}₂CH₃C}]-salicylaldehyde compound (493 mg,0.623 mmol) and 2,3-diamino-2,3-dimethylbutane (36 mg, 0.311 mmol) wereintroduced into a flask. Ethanol (4 mL) was added as the solvent,molecular sieves (180 mg) were introduced and the resultant mixture wassubjected to reflux for 12 hours under nitrogen atmosphere. The mixturewas filtered through a Celite pad to remove the molecular sieves andremoved the solvents under reduced pressure to obtain the product asyellow solid. Co(OAc)₂ (55 mg, 0.31 mmol) was added to the flask andethanol (10 mL) as the solvent. The resulting mixture was stirred for 5hours at room temperature. Solvents were removed under reduced pressure,and the resulting compound was triturated twice with diethyl ether toobtain the red color compound. 2,4-dinitrophenol (57 mg, 0.311 mmol) wasadded and the mixture was dissolved in methylene chloride (10 mL) andstirred for 12 hours in the presence of oxygen.Sodium-2,4-dinitrophenolate (320 mg, 1.56 mmol) was added and theresulting reaction mixture was stirred for further 12 hours. Thesolution was filtered over a pad of celite and the solvents were removedunder reduced pressure to obtain 736 mg of a dark red solid product.

¹H NMR (DMSO-d₆, 38° C.): δ 8.62 (br, 4H, (NO₂)₂C₆H₃O), 7.87 (br, 4H,(NO₂)₂C₆H₃O), 7.72 (br, 2H, CH═N), 7.50 (br, 2H, m-H), 7.35 (br, 2H,m-H), 6.47 (br, 4H, (NO₂)₂C₆H₃O), 3.11 (br, 32H, NCH₂), 2.70 (s, 6H,CH₃), 1.66-1.22 (br, 82H), 0.88 (br, 36H, CH₃) ppm. ¹³C{¹H} NMR(DMSO-d₆): δ 164.67, 159.42, 132.30, 129.71, 128.86 (br), 128.46 (br),127.42 (br), 124.05 (br), 118.84, 73.92, 57.74, 57.19, 25.94, 23.33,22.61, 21.05, 18.73, 16.68, 16.43, 12.93 ppm.

Example 8 Preparation of Complex 12

Salen ligand (500 mg, 0.301 mmol) obtained from 3-methyl-5-[{BF₄⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde compound and Co(OAc)₂ (53 mg, 0.30mmol) were introduced into a flask, and added ethanol (15 mL) assolvent, the resulting solution was stirred for 3 hours under nitrogenatmosphere. The solvent was removed under reduced pressure, and theresultant compound was triturated twice with diethyl ether to obtain redcolor compound. The compound was dissolved in methylene chloride (10mL). Then, HBF₄ (49 mg, 0.30 mmol) was added to the resultant solutionin the presence of oxygen, followed by stirring for additional 3 hours.After that, the solvents were removed under reduced pressure to obtain520 mg of a pure compound. Complex 12 was prepared according to theknown method developed by the present inventors (Angew. Chem. Int. Ed.,2008, 47, 7306-7309).

Example 9 Preparation of Complex 13

Complex 13 was obtained with a Salen ligand obtained from3-t-butyl-5-[{BF₄ ⁻Bu₃N⁺(CH₂)₃}₂CH}]-salicylaldehyde compound in thesame manner as described in Example 8.

¹H NMR (DMSO-d₆, 40° C.): δ 7.68 (s, 1H, CH═N), 7.36 (s, 1H, m-H), 7.23(s, 1H, m-H), 3.61 (br, 1H, NCH), 3.31-2.91 (br, 16H, NCH₂), 2.04 (br,1H, cyclohexyl-CH₂), 1.89 (br, 1H, cyclohexyl-CH₂), 1.74 (s, 9H,C(CH₃)₃), 1.68-1.35 (br, 20H, CH₂), 1.32-1.18 (br, 12H, CH₂), 0.91 (t,J=7.2 Hz, 18H, CH₃) ppm. ¹³C{¹H} NMR (DMSO-d₆): δ 161.66, 160.42,140.90, 129.71, 128.38, 127.31, 117.38, 67.40, 55.85, 33.89, 31.11,28.70, 27.70 (br), 22.58, 21.29, 19.47, 17.45, 15.21, 11.69 ppm.

Example 10 Preparation of Complex 14

Compound 10 was dissolved in propylene oxide, and the solution wasallowed to stand for 1 hour and then removed the solvents under vacuumto obtain the complex 14.

¹H NMR (DMSO-d₆): δ 8.59 (s, 1H, (NO₂)₂C₆H₃O), 8.42 (s, 1H,spiro-Meisenheimer anion), 7.74 (s, 1H, (NO₂)₂C₆H₃O), 7.39-6.98 (m, 3H,m-H, CH═N), 6.81 (s, 1H, spiro-Meisenheimer anion), 6.29 (s,(NO₂)₂C₆H₃O), 5.35 (s, 1H, spiro-Meisenheimer anion), 4.43-4.29 (m, 1H,spiro-Meisenheimer anion), 4.21-3.99 (m, 2H, spiro-Meisenheimer anion),3.21 (br, 1H, NCH), 3.09 (br, 16H, NCH₂), 2.93 (m, 3H,spiro-Meisenheimer anion), 2.62 (s, 3H, CH₃), 1.98 (br, 1H,cyclohexyl-CH₂), 1.62-1.39 (br, 20H, CH₂), 1.39-1.15 (br, 15H, CH₂,CH₃), 0.91 (br, 18H, CH₃) ppm.

Example 11 Preparation of Complex 35a

Preparation of 1,7-dichloro-4-methylheptan-4-ol

Under nitrogen atmosphere, 1,7-dichloro-4-methylheptan-4-one (17.40 g,95.04 mmol) was dissolved in diethyl ether (285 mL). The reactionmixture was cooled to −78° C. and MeLi (1.5 M solution in diethyl ether,80.97 g, 142.56 mmol) was added dropwise using a syringe under nitrogenatmosphere. The resulting mixture was stirred for 2 hours at −78° C.Water (170 mL) was added at −78° C. to quench the reaction path. Thereaction mixture was extracted three times with diethyl ether (300 mL)and collected the organic phases. Combined the organic layers and driedover anhydrous magnesium sulfate, followed by filtration, and thesolvents were removed by a rotary evaporator under reduced pressure toobtain 17.99 g (yield 95%) of the title compound, which may be used forthe subsequent reaction without further purification.

¹H NMR (CDCl₃): δ. 3.59 (t, J=6.4 Hz, 4H, CH₂Cl), 1.90-1.86 (m, 4H,CH₂), 1.64-1.60 (m, 4H, CH₂), 1.23 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR(CDCl₃): δ. 72.32, 45.88, 39.51, 27.60, 27.23.

Preparation of Complex 35a

Under nitrogen atmosphere, o-cresol (78.17 g, 722.82 mmol),1,7-dichloro-4-methylheptane-4-ol (17.99 g, 90.35 mmol) and AlCl₃ (13.25g, 99.39 mmol) were mixed in a round bottom flask and stirred overnight.Next, diethyl ether (500 mL) and water (300 mL) are introduced theretoto quench the reaction. The organic layers were collected, and theaqueous layer was further extracted three times with diethyl ether (300mL). Combined the organic phases and dried over anhydrous magnesiumsulfate, followed by filtration, and the solvents were removed by arotary evaporator under reduced pressure. The excess o-cresol wasremoved by vacuum distillation (2 mmHg) at an oil bath temperature of85° C. The compound remaining in the flask has a purity sufficient to beused for the subsequent reaction without further purification. In thismanner, 25.40 g of complex 35a is obtained (yield 97%).

¹H NMR (CDCl₃): δ. 7.01 (d, J=2.0 Hz, 1H, m-H), 6.97 (dd, J=8.0 Hz, 2.0Hz, 1H, m-H), 6.72 (d, J=8.0 Hz, 1H, o-H), 4.85 (s, 1H, OH), 3.45 (t,J=6.4 Hz, 4H, CH₂Cl), 2.27 (s, 3H, CH₃), 1.86-1.44 (m, 8H, CH₂), 1.30(s, 3H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 151.79, 138.67, 129.06,125.02, 123.45, 114.85, 46.20, 41.12, 39.95, 28.09, 24.22, 16.58

Example 12 Preparation of Complex 39a

Preparation of Complex 36a

Complex 35a (25.40 g, 87.83 mmol) was dissolved in tetrahydrofuran (650mL) under nitrogen atmosphere. Paraformaldehyde (10.55 g, 351.32 mmol),magnesium chloride (33.52 g, 351.32 mmol) and triethylamine (37.31 g,368.89 mmol) were introduced, into a flask under nitrogen atmosphere,and a refluxed for 5 hours under nitrogen atmosphere. The solvent wasremoved by a rotary evaporator under reduced pressure and methylenechloride (500 mL) and water (300 mL) were added. The resultant mixturewas filtered over a pad of Celite to obtain a methylene chloride layer.The aqueous layer was further extracted three times with methylenechloride (300 mL) and combined organic layers, dried over anhydrousmagnesium sulfate and filtered, the solvents were removed by a rotaryevaporator under reduced pressure to obtain an oily compound. Theremaining trace amount of triethylamine is removed by a vacuum pump. Theresultant compound has high purity as determined by NMR analysis and canbe used for the subsequent reaction without further purification. Inthis manner 26.75 g of complex 36a was obtained (yield 96%).

¹H NMR (CDCl₃): δ. 11.14 (s, 1H, OH), 9.87 (s, 1H, CH═O), 7.33 (d, J=2.4Hz, 1H, m-H), 7.26 (d, J=2.4 Hz, 1H, m-H), 3.47 (t, J=6.4 Hz, 4H,CH₂Cl), 2.30 (s, 3H, CH₃), 1.90-1.40 (m, 8H, CH₂), 1.35 (s, 3H, CH₃)ppm. ¹³C{¹H} NMR (CDCl₃): δ. 196.87, 158.22, 137.56, 136.11, 128.91,119.69, 45.88, 40.67, 39.98, 27.96, 24.06, 15.81.

Preparation of Complex 37a

Complex 36a (26.75 g, 84.32 mmol) was dissolved in acetonitrile (107mL). Sodium iodide (126.39 g, 843.18 mmol) was added to the solution andthe resulting solution was refluxed for overnight. After cooling themixture to room temperature, water (300 mL) was added to quench thereaction path. The resultant solution was extracted three times withdiethyl ether (300 mL) and collected the organic layers. The collectedorganic layer was dried over anhydrous magnesium sulfate, followed byfiltration, and the solvents were removed by a rotary evaporator underreduced pressure. The resultant compound was purified by columnchromatography using silica gel, eluting with hexane-toluene (5:1) aseluent to obtain pure complex 37a (22.17 g, yield 83%).

¹H NMR (CDCl₃): δ. 11.14 (s, 1H, OH), 9.87 (s, 1H, CH═O), 7.33 (d, J=2.4Hz, 1H, m-H), 7.25 (d, J=2.4 Hz, 1H, m-H), 3.14-3.09 (m, 4H, CH₂I), 2.30(s, 3H, CH₃), 1.87-1.43 (m, 8H, CH₂), 1.34 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR(CDCl₃): δ. 196.85, 158.20, 137.50, 136.09, 128.85, 126.93, 119.62,44.28, 39.95, 28.66, 24.16, 15.81, 7.99.

Preparation of Complex 38a

Complex 37a (8.56 g, 17.01 mmol) was dissolved in methylene chloride (97mL) under nitrogen atmosphere. (±)-trans-1,2-diaminocyclohexane (0.97 g,8.50 mmol) was added and stirred for overnight. The solvents wereremoved under reduced pressure to obtain pure complex 38a (9.00 g, yield98%).

¹H NMR (CDCl₃): δ. 13.48 (s, 1H, OH), 8.31 (s, 1H, CH═N), 7.04 (d, J=1.6Hz, 1H, m-H), 6.91 (d, J=1.6 Hz, 1H, m-H), 3.38-3.35 (m, 1H,cyclohexyl-CH), 3.08-3.03 (m, 4H, CH₂I), 2.25 (s, 3H, CH₃), 1.96-1.89(m, 2H, cyclohexyl-CH₂), 1.96-1.43 (m, 10H, cyclohexyl-CH₂ and CH₂),1.26 (s, 3H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 165.01, 157.31, 136.12,131.35, 126.93, 125.54, 117.67, 72.94, 44.47, 39.79, 33.73, 28.72,24.57, 24.32, 16.28, 8.38, 8.26.

Preparation of Complex 39a

Complex 38a (0.855 g, 0.79 mmol) is dissolved into acetonitrile (8.5 mL)under nitrogen atmosphere, tributyl amine (1.17 g, 6.32 mmol) was addedand the resulting solution was refluxed for 48 hours. Solvents wereremoved by a rotary evaporator under reduced pressure. Diethyl ether (20mL) was added to the obtained slurry and titurated for 15 minutes toprecipitate the product as solid. The ether layer was decanted and theabove process was repeated twice to obtain beige solid compound. Thesolid compound was added gradually to solution of AgBF₄ (0.642 g, 3.30mmol) in ethanol (40 mL) with stirring. The reaction mixture wasagitated for 24 hours under light-shielded atmosphere, and the resultantAgI was removed by filteration over a pad of celite. The solvents wereremoved under vacuum. Then, the resultant compound was dissolved inmethylene chloride (6 mL), and further filtered through a Celite pad toremove floating materials. The resultant product was purified by columnchromatography using silica, eluting with methylene chloride-ethanol(5:1) as eluent to obtain the 39a (1.23 g, yield 90%).

¹H NMR (CDCl₃): δ. 13.55 (s, 1H, OH), 8.42 (s, 1H, CH═N), 7.12 (s, 1H,m-H), 7.08 (s, 1H, m-H), 3.38 (br, 1H, cyclohexyl-CH), 3.06 (br, 16H,NCH₂), 2.20 (s, 3H, CH₃), 1.88-1.84 (br, 2H, cyclohexyl-CH₂), 1.68-1.26(br, 36H), 0.87-0.86 (br, 18H, CH₃) ppm. ¹³C{¹H} NMR (CDCl₃): δ. 165.23,157.79, 135.21, 131.17, 127.18, 125.76, 117.91, 72.05, 59.16, 58.63,40.16, 38.10, 37.71, 26.45, 24.91, 23.90, 20.31, 19.80, 17.30, 16.01,13.97, 13.80, 13.79

Example 13 Preparation of Complex 40a

Preparation of Complex 40a

Complex 39a (100 mg, 0.06 mmol) and Co(OAc)₂ (10.7 mg, 0.06 mmol) wereintroduced into a flask and ethanol (3 mL) was added as the solvent. Thereaction mixture was stirred at room temperature for 3 hours and removedthe solvents under reduced pressure. The obtained product was triturated2 times with diethyl ether to obtain the red solid compound. Theresidual solvents were removed completely by applying reduced pressure.Methylene chloride (3 mL) was added to dissolve the compound. Then,2,4-dinitrophenol (11.1 mg, 0.06 mmol) was introduced and the reactionmixture was stirred for 3 hours under oxygen atmosphere. Under oxygenatmosphere, sodium-2,4-dinitrophenolate (74.5 mg, 0.30 mmol) wasintroduced and the mixture was stirred for overnight. The resultantsolution was filtered over a pad of celite and the solvents were removedunder reduced pressure to obtain the complex 40a (138 mg, yield 100%).

¹H NMR (DMSO-d₆, 38° C.): δ. 8.65 (br, 2H, (NO₂)₂C₆H₃O), δ. 7.88 (br,3H, (NO₂)₂C₆H₃O, CH═N), 7.31 (br, 2H, m-H), 6.39 (br, 2H, (NO₂)₂C₆H₃O),3.38 (br, 1H, cyclohexyl-CH), 3.08 (br, 16H, NCH₂), 2.64 (s, 3H, CH₃),2.06-1.85 (br, 2H, cyclohexyl-CH₂), 1.50-1.15 (br, 36H), 0.86 (br, 18H,CH₃) ppm.

Example 14 Structural Analysis of Complexes

Complexes 7 and 8 obtained from Examples 3 and 4 are subjected tointensive structural analysis.

(1) ¹H, ¹³C and ¹⁵N NMR Spectra and IR Spectrum

FIGS. 1, 2, 3, 4 and 5 show ¹H NMR spectrum, ¹³C NMR spectrum and ¹⁵N

NMR spectrum of compounds 7 and 8 in DMSO-d₆ as a solvent, and ¹H NMRspectra of compounds 7 and 8 in THF-d₈ and CD₂Cl₂ as solvents. It can beseen that the two compounds show clearly different behaviors. In thecase of complex 8 prepared from a ligand wherein R is t-butyl, sharpsignals appear in both ¹H NMR spectrum and ¹³C NMR spectrum. This is atypical behavior of tetradentate Salen-Co (III) compound. In the ¹⁵N NMRspectrum, only one signal appears at −163.43 ppm regardless oftemperature.

In the ¹H NMR spectrum and ¹³C NMR spectrum of complex 7 (Example 3)prepared from a ligand wherein R is methyl, a very complex and broadsignal appears at room temperature, a simple and broad signal isobtained at 40° C., and a sharp signal is obtained at 80° C. The ratioof [DNP]/[Salen-unit] obtained from integration of the ¹H NMR spectrumis near 4.0 rather than 5.0 observed in the case of complex 8. Asdetermined by ¹⁵N NMR, two signals appear at −156.32 and −159.21 ppmunder room temperature, a broad signal including two fused signalsappears at 40° C., and only one sharp signal appears at 80° C.

Complexes 7 and 8 show significantly different behaviors as determinedby ¹H NMR spectrometry in THF-d₈ or CD₂Cl₂ (FIG. 4). In the ¹H NMRspectrum of complex 8, a set of Salen-unit signals appears and a verybroad DNP signal appears. Especially, some signals appear at an abnormalrange, −2 to 0 ppm. This suggests that some paramagnetic compounds arepresent. In the case of ¹H NMR spectrum of complex 7, only one set ofSalen-unit signals appears, which has a significantly different chemicalshift from complex 8. Broad DNP signals are observed at 7.88, 8.01 and8.59 ppm. However, the ratio of [DNP]/[Salen-unit] integration is about2.0, and only two DNP signals are observed among the four DNP signalsobserved in DMSO-d₆ with the remaining two non-observed. As determinedin CD₂Cl₂, ¹H NMR spectrometric behaviors of complexes 7 and 8 aresimilar to those in THF-d₈.

In the ¹⁵N NMR spectrum in THF-d₈, a sharp signal appears at −166.80 ppm(complex 8) or −154.32 ppm (complex 7). It is not reasonable to regardsuch a difference in chemical shift values of 12.5 ppm as a differencecaused merely by the effect of substituents. It is reported thatchemical shift values in the ¹⁵N NMR spectrum of imine compounds(—N═C—C₄H₄—X) and hydrazone compounds (N—N═C—C₄H₄—X) follow the Hammetttype equation with a gradient of about 10. Considering a differencecaused by the methyl and t-butyl substituents, the two substituentscontribute a difference in chemical shift values of 1 ppm or less(Neuvonen, K.; Fülöp, F.; Neuvonen, H.; Koch, A.; Kleinpeter, Pihlaja,K. J. Org. Chem. 2003, 68, 2151). In addition, in the case ofdipyrrolmethene ligand and zinc (II) compounds obtained therefrom,substitution of hydrogen with ethyl provides a difference in chemicalshift values of 2 ppm in ¹⁵N NMR spectrometry (Wood, T. E.; Berno, B.;Beshara, C. S.; Thompson, Alison, J. Org. Chem. 2006, 71, 2964). Infact, when viewed from the state of ligands used for preparing complexes7 and 8, chemical shift difference is as low as 2.86 ppm. Therefore, itcan be thought that the value of chemical shift of 12.5 ppm as observedherein results from different structures of the two complexes, i.e.complexes 7 and 8. When observing ¹⁵N NMR spectrum in THF-d₈ whilevarying temperature, complex 7 shows a relatively broadened signal asthe temperature decreases, resulting in a full width at half maximum(FWHM) of 10 ppm at −75° C. On the other hand, complex 8 shows arelatively sharp signal at −75° C. as determined by a FWHM of 1.5 ppm.The above results suggest that complex 8 has a general structure ofrigid Salen-Co (III) compounds to which all of the four ligands of Salenare coordinated, while complex 7 has a more flexible structure differenttherefrom.

As shown in FIG. 5, the two complexes show clearly different signals ina range of 1200-1400 cm⁻¹ corresponding to the symmetric vibration of—NO₂ in IR spectra.

(2) Suggestion of Structure of Complexes

It can be said that complex 8 has a structure of a general Salenligand-containing cobalt complex in which all of the four ligands ofSalen are coordinated to cobalt, when observed by the ¹H, ¹³C, and ¹⁵NNMR spectra. After carrying out ICP-AES, elemental analysis and ¹⁹F NMRspectrometry, it is found that one equivalent of NaBF₄. is inserted intothe complex. In the ¹H NMR spectrum, a broad DNP signal is observed,which suggests that the DNP ligand undergoes continuousconversion/reversion between the coordinated state and thede-coordinated state. As a part of the conversion/reversion, asquare-pyramidal cobalt compound may be present transiently and thesquare-pyrimidal compound is known to be a paramagnetic compound [(a)Konig, E.; Kremer, S.; Schnakig, R.; Kanellakopulos, B. Chem. Phys.1978, 34, 79. (b) Kemper, S.; Hrobàrik, P.; Kaupp, M.; Schlörer, N. E.J. Am. Chem. Soc. 2009, 131, 4172.]. Therefore, an abnormal signal isalways observed at −2 to 0 ppm in the ¹H NMR spectrum of complex 8.

When complex 7 has the above-mentioned non-imine coordinated structure,the analytic data may be understood. In addition, the structure isdemonstrated through the following DFT calculation and electrochemicalexperiments. The structure is characterized in that four DNP ions, whichare conjugate anions of quaternary ammonium salt, are coordinatedinstead of imine. The last operation of the catalyst preparationincludes reaction with 5 equivalents of NaDNP suspended in CH₂Cl₂ toperform a change of [BF₄ ⁻] into DNP anion. [DNP]/[Sales-unit]integration ratio is 4.0 and this is not significantly changed even whenusing a more excessive amount of NaDNP (10 equivalents) or whenincreasing the reaction time. In other words, one among the four BF₄remains unsubstituted. Since BF₄ signals are observed in ¹⁹F NMR but Na⁺ion is not observed from ICP-AES analysis unlike complex 8, it can beseen that BF₄ anion is present as a conjugate anion of quaternaryammonium salt. Even when preparing a catalyst with ligands having morequaternary ammonium salt units like complex 9, only the compound havingfour DNP ligands are observed even in the presence of a significantlyexcessive amount of NaDNP and even after a longer time. It is thoughtthat an octahedral coordination compound having two Salen-phenoxyligands and four DNP ligands is obtained in methylene chloride as asolvent, and formation of the octahedral compound causes the anionexchange. Cobalt (III) metal is classified into hard acid, and the hardacid prefers DNP to imine-base, resulting in the compound with such adifferent structure. In the case of complex 8, steric hindrance oft-butyl hinders formation of such a compound. The octahedral cobalt(III) compound in which cobalt has a charge of −3 is previously known[(a) Yagi, T.; Hanai, H.; Komorita, T.; Suzuki T.; Kaizaki S. J. Chem.Soc., Dalton Trans. 2002, 1126. (b) Fujita, M.; Gillards, R. D.Polyhedron 1988, 7, 2731.]

Complexes 5, 9 and 10 provide ¹H and ¹³C NMR spectrum and IR spectrumbehaviors similar to complex 7, and thus may be regarded as a complexwith a different coordination system having no imine coordination.Particularly, complex 5 has been regarded as a general Salen-compoundstructure having imine coordination like complex 8 in the previouslyknown publication of the present inventors (Angew. Chem. Int. Ed., 2008,47, 7306-7309) and patent applications [Korean Patent Application No.10-2008-0015454 (2008 Feb. 20, titled with “METHOD FOR RECOVERINGCATALYST FROM COPOLYMER PREPARATION PROCESS”, Bun Yeoul Lee, Sujith S,Eun Kyung Noh, Jae Ki Min, “A PROCESS PRODUCING POLYCARBONATE AND ACOORDINATION COMPLEXES USED THEREFOR” PCT/KR2008/002453 (2008 Apr. 30);Sujith S, Jae Ki Min, Jong Eon Seong, Sung Jea Na, and Bun Yeoul Lee* “AHIGHLY ACTIVE AND RECYCLABLE CATALYTIC SYSTEM FOR CO₂/(PROPYLENEOXIDE)”]. However, it is found herein that complex 5 has such adifferent structure.

Complexes 6 and 11 provide ¹H and ¹³C NMR spectrum and IR spectrumbehaviors similar to complex 8, and thus may be regarded as a generalSalen-compound structure having imine coordination.

(3) DFT Calculation

DFT calculation is carried out to determine the structures and energylevels of complex 7 with a different coordination structure having noimine coordination, and another complex that are an isomer of complex 7and have a general imine coordination structure, wherein two DNP ligandsare coordinated at the axial site and the remaining two are present in afree state. FIG. 6 shows the most stable conformation of complex 7obtained from the calculation. As can be seen from FIG. 6, complex 7with a different structure having no imine coordination as disclosedherein has a more stable energy level than the general imine-coordinatedstructure by 132 kcal/mol. Such a difference in energy levels issignificant.

(4) Movability of DNP Ligand

When observed from ¹H NMR in methylene chloride used in the last anionexchange reaction during the preparation of a catalyst, complexes 7, 9and 10 show DNP signals at 8.4, 8.1 and 7.9 ppm with a[DNP]/[Salen-unit] integration ratio of 2.0 (FIG. 4). In other words,only two DNP ligands are observed among the four DNP ligands with theremaining two non-observed. This is because two DNP ligands undergocontinuous conversion/reversion between the coordinated state and thenon-coordinated state at a level of NMR time.

On the other hand, in the case of complex 5, four DNP signals areobserved at the same range. The DNP signals observed herein has achemical shift greatly different from the chemical shift of[Bu₄N]⁺[DNP]⁻. Thus, it is though that the observed signals result fromDNP coordinated in the complex. In other words, in the case of complexes7, 9 and 10, two DNP ligands are coordinated and the remaining twoundergo continuous conversion/reversion between the coordinated stateand de-coordinated state in methylene chloride solvent at roomtemperature. In the case of complex 5, four DNP ligands are coordinated.FIG. 7 is a reaction scheme illustrating a change in the state of DNP atroom temperature depending on the solvent, in the case of a compoundwith a different coordination system having no coordination with imine.As demonstrate by FIG. 7, the above statement that the complex obtainedfrom the last anion exchange reaction has an octahedral coordinationstructure having two Salen-phenoxy ligands and four DNP ligands conformsto the structure adopted from the DFT calculation.

In addition, as observed from ¹H NMR spectrum of complex 7 measured inTHF-d₈ at room temperature, signals corresponding to the two coordinatedDNP ligands are observed at 8.6, 8.1 and 7.9 ppm (FIG. 4). When thetemperature is reduced to 0° C., the signals become sharper and a signalcoupling behavior is observed. The coordinated DNP signals may be moreclearly understood by determining ¹H-¹H COSY NMR spectrum (FIG. 8). Whenthe temperature is further reduced to −25° C., a new DNP signal isobserved (marked with in FIG. 8). The new signal has a similar chemicalshift to [Bu₄N]⁺DNP⁻. Thus, the new signal may be regarded as DNPremaining in the de-coordinated state for a long time. At 70° C., fourDNP ligands are observed as one set of broad signals at 9.3, 9.0 and 7.8ppm. This is similar to the chemical shift of the coordinated DNPsignal, and it is thought that all of the four DNP ligands remain in thecoordinated state for a long time. In other words, as the temperatureincreases, DNP ligands may be more adjacent to the cobalt center. Thede-coordinated DNP ligands are surrounded with solvent molecules,resulting in a decrease in entropy. Such de-coordination accompaniedwith a decrease in entropy is preferred at low temperature. Thus,de-coordinated signals are observed at reduced temperature, while ashift into the coordinated state is observed at high temperature.Similarly, a transition from a contact ion pair to a solvent separatedion pair at reduced temperature is well known [(a) Streitwieser Jr., A.;Chang, C. J.; Hollyhead, W. B.; Murdoch, J. R. J. Am. Chem. Soc. 1972,94, 5288. (b) Hogen-Esch, T. E.; Smid, J. J. Am. Chem. Soc. 1966, 88,307.(c) Lü, J.-M.; Rosokha, S. V.; Lindeman, S. V.; Neretin, I. S.;Kochi, J. K. J. Am. Chem. Soc. 2005, 127, 1797]. FIG. 8 shows VT ¹H NMRspectrum of compound 7 in THF-d₈.

Salen Complex 8 coordinated with imine shows highly different ¹H NMRspectrum in THF-d₈, as compared to complex 7. This demonstrates thatcomplexes 7 and 8 have different structures. When reducing thetemperature to 0° C., all DNP signals become broadened so that anysignals may not be observed. At −25° C., a relatively sharp DNP signalset is observed at 8.1, 7.6 and 6.8 ppm with a [DNP]/[Salen-unit]integration ratio of 2.0. In addition, a significantly broad set ofsignals is observed at 8.9, 8.0 and 6.8 ppm, and these chemical shiftvalues are similar to the chemical shift values (8.7, 8.0 and 6.8 ppm)of DNP remaining in the de-coordinated state for a long time as observedin complex 7. At −50° C., the two sets of signals become sharper so thattwo sets of DNP signals may be seen clearly. The DNP signals observed at8.1, 7.6 and 6.8 ppm may correspond to two DNP ligands coordinated atthe axial site of the conventional Salen coordination complex. Anotherset of signals observed at 8.9, 8.0 and 6.8 ppm may correspond to thede-coordinated state.

The state of DNP in THF at room temperature depending on the structureof ligand is demonstrated via ¹H NMR. In the case of complex 7, a set ofsignals of two coordinated DNP ligands is observed and the remaining twoDNP ligands are not observed. This suggests that the two DNP ligandsthat are not observed herein undergo continuous conversion/reversionbetween the coordinated state and the de-coordinated state. On the otherhand, in the cases of complexes 5, 9 and 10, two sets of signals, i.e.,one set of two coordinated DNP signals and another set of signals of twoDNP ligands remaining mainly in the de-coordinated state are observed.The signals of two DNP ligands remaining mainly in the de-coordinatedstate as observed in complexes 9 and 10 are broader than thecorresponding signals in complex 5. This suggests that the two DNPligands in complexes 9 and 10 remain in the de-coordinated state for ashorter time as compared to complex 5. As a result, the degree ofretention (binding affinity to cobalt) of the two DNP ligands remainingmainly in the de-coordinated state is in order of 7>9 and 10>5.

As determined from ¹H NMR spectrum of complexes 5, 7, 9 and 10 inDMSO-d₆ at 40° C., four DNP ligands are observed as a set of broadsignals (FIG. 1). The chemical shift values of the signals (8.6, 7.8 and6.4 ppm) are similar to the chemical shift values of [Bu₄N]⁺DNP⁻ (8.58,7.80 and 6.35 ppm). Therefore, it can be said that the four DNP ligandsremain mainly in the de-coordinated state at 40° C. However, such broadsignals also suggest that the ligands undergo continuousconversion/reversion between the coordinated state and thede-coordinated state. At room temperature, another set of DNP signalsare observed at 8.5, 8.1 and 7.8 ppm along with a set of signals of DNPligands remaining mainly in the de-coordinated state with an integrationratio of 1:3. The less observed DNP signals have similar chemical shiftvalues as compared to the chemical shift values of the coordinated DNPligands observed in THF and methylene chloride. Thus, the signals maycorrespond to coordinated DNP ligands. In other words, in DMSO at roomtemperature, one DMP remains mainly in the coordinated state and theother three DMP ligands remain in the de-coordinated state. It isthought that DMSO is coordinated at the vacant site generated byde-coordination of DNP. DMSO is coordinated well to hard acid such ascobalt (III) metal.

(5) Complicated NMR Spectrometric Analysis Observed in DMSO-D₆

The complicated ¹H, ¹³C and ¹⁵N NMR spectra of complex 7 observed inDMSO-d₆ may be understood through the above-described non-iminecoordinated structure and the state of DNP. In the structure and stateof complex 7 in DMSO at room temperature as shown in FIG. 7, two phenoxyligands contained in one Salen-unit are subjected to differentsituations. One phenoxy ligand is at trans-position to DMSO, and theother is at trans-position to DNP. Therefore, two signals are observedin ¹⁵N NMR spectrum (FIG. 3), and a part of aromatic signals is dividedat a ratio of 1:1 in ¹H and ¹³C NMR (FIGS. 1 and 2). Especially,NCH₂CH₂N signal is divided into three signals at 4.3, 4.15 and 4.1 ppmwith a ratio of 1:1:2. After the analysis through ¹H-¹H COSY NMRspectrometry, it can be seen that three signals are derived from oneNCH₂CH₂N-unit (FIG. 1). In the structure obtained by the DFTcalculation, complex 7 shows a conformation of ═NCH₂CH₂N=unit and issimilar to the structure as illustrated in FIG. 6. In the abovestructure, complex 7 may not be converted into a structural isomer ofthe cobalt octahedral structure. Thus, the structure having three DMSOcoordinations and one DNP coordination is chiral. Due to such chirality,two hydrogen atoms of N—CH₂ show NMR shift values at differentpositions. In the case of a complex with a chiral center, such ascomplex 5 or 10, ¹H and ¹³C NMR spectra are more complicated. As thetemperature increases to 40° C., two coordinated DNP signals disappearand one broad signal appears. In this case, the asymmetric coordinationenvironment is broken and a simple Salen-ligand signal appears. Sincethe coordination environment around cobalt is symmetric in THF andCH₂Cl₂ at room temperature as shown in FIG. 7, a sharp Salen-ligandsignal appears in ¹H, ¹³C and ¹⁵N NMR.

(6) Cyclic Voltammetry (CV) Test

CV test also indirectly demonstrates that complexes 5 and 6 havedifferent structures. If complexes 5 and 6 have the same structure,complex 5 having a methyl substituent is expected to cause reductionmore easily. This is because methyl has lower electron donating propertythan t-butyl, and thus the cobalt center has less abundant electrons sothat the electrons go into the cobalt center more easily. However, theopposite results are observed. Complex 5 with a methyl substituentcauses reduction at a more negative potential than complex 6. It isobserved that complexes 5 and 6 have a E_(1/2) value of Co(III/II) of−0.076V and −0.013V, respectively, versus SCE. The difference, 63 mV, inreduction potentials between the two complexes is significant. Areduction potential difference of 59 mV from the Nernst equation[E=E°−(0.0592)log {[Ox]/[Red]}] means a difference in [Co(II)]/[Co(III)]ratios of 10 times at the same potential.

On the other hand, it is expected that complexes 12 and 13 having no DNPligands have the same general imine-coordinated structure regardless ofmethyl or t-butyl substitution in a non-coordinatable solvent such asmethylene chloride. After carrying out CV study with complexes 12 and 13in methylene chloride, the two complexes show the same reductionpotential (0.63 V vs. SCE). In other words, there is no difference inreduction potentials between methyl substitution and t-butylsubstitution under the same structure. Thus, the above difference inreduction potentials suggests that the two complexes have differentcoordination systems. When the solvent is changed from CH₂Cl₂ to DMSO,the reduction potential difference appears again. The reductionpotentials of complexes 12 and 13 observed in DMSO (−0.074 and −0.011 Vvs. SCE) are similar to the reduction potentials of complexes 5 and 6observed in DMSO (−0.076 and −0.013 V vs. SCE). Since DMSO iscoordinated well to cobalt (III) metal, in DMSO as a solvent, complex 12is converted into a complex with a different coordination system, suchas complex 5 having no imine coordination, while four DMSO ligands arecoordinated to complex 12 having a methyl substituent.

(7) Initiation Reaction

Complex 10 reacts with propylene oxide. FIG. 9 is ¹H NMR spectrumillustrating the reaction between complex 10 or 8 and propylene oxide.The signal marked with ‘*’ is a newly generated signal that correspondsto the anion of Meisenheimer salt shown in complex 14. The oxygen atomof alkoxide obtained by the attack to propylene oxide coordinated withDNP further attacks ipso-position of the benzene ring, so that the anionof Meisenheimer salt is formed. Complicated aromatic signals of Salenare observed at 7.0-7.4 ppm. However, this is not caused by the breakageof the Salen-unit. When an excessive amount of acetic acid is added tothe compound prepared after the reaction with propylene oxide, simplethree Salen aromatic signals are observed. This suggests that theSalen-unit is not broken. The anion of Meisenheimer salt is stopped at a[Meisenheimer anion]/[DNP] integration ratio of 1:1. During the firstone hour, DNP is converted rapidly into the anion of Meisenheimer saltso that the [Meisenheimer anion]/[DNP] integration ratio reaches 1:1.However, the conversion does not proceed any longer, and thus theintegration ratio is unchanged even after 2 hours. The anion ofMeisenheimer salt is a previously known compound [(a) Fendler, E. J.;Fendler, J. H.; Byrne, W. E.; Gruff, C. E. J. Org. Chem. 1968, 33, 4141.(b) Bernasconi, C. F.; Cross, H. S. J. Org. Chem. 1974, 39, 1054)].Conversion of DNP into the anion of Meisenheimer salt is significantlylowered in the presence of a certain amount of water. When 5 equivalentsof water are present per equivalent of cobalt, the conversion rate isnot significantly changed. However, introduction of 50 equivalents ofwater causes a rapid drop in the conversion rate, so that the[Meisenheimer anion]/[DNP] integration ratio becomes 0.47 after 1 hour,becomes 0.53 after 2 hours, and remains at 0.63 even after 4 hours whilenot providing complex 14 (FIG. 8).

The reactivity of the general imine-coordinated complex 8 with propyleneoxide is different from that of the non-imine coordinated complex 10.Although the same anion of Meisenheimer salt is observed, the[Meisenheimer anion]/[DNP] integration ratio is not stopped at 1.0 butgradually increases over time (0.96 after 1 hour; 1.4 after 2 hours; 1.8after 7 hours; and 2.0 after 20 hours). Further, unlike the behavior ofcomplex 10, complex 8 shows a relatively large amount of broad signalsbetween −1 ppm and 0.5 ppm. This suggests that reduction into aparamagnetic cobalt (II) compound occurs. The broad signal graduallyincreases over time. The cobalt (II) compound has no catalytic activity.

Example 15 Preparation of Carbon Dioxide/Propylene Oxide Copolymer

(a) Copolymerization Using Complexes of Examples 3-10 as Catalyst

To a 50 mL bomb reactor, any one complex obtained from Examples 3-10(used in an amount calculated according to a ratio of monomer/catalystof 7.58) and propylene oxide (10.0 g, 172 mmol) are introduced in a drybox and the reactor is assembled. As soon as the reactor is removed fromthe dry box, carbon dioxide is introduced under a pressure of 18 bar,the reactor is introduced into an oil bath controlled previously to atemperature of 80° C. and agitation is initiated. The time at whichcarbon dioxide pressure starts to be decreased is measured and recorded.After that, the reaction is carried out for 1 hour, and then carbondioxide gas is depressurized to terminate the reaction. To the resultantviscous solution, monomers (10 g) are further introduced to reduce theviscosity. Then, the resultant solution is passed through a silica gelcolumn [400 mg, Merck, 0.040-0.063 mm particle diameter (230-400 mesh)]to obtain a colorless solution. The monomers are removed bydepressurization under reduced pressure to obtain a white solid. Theweight of the resultant polymer is measured to calculate turnover number(TON). The polymer is subjected to ¹H NMR spectrometry to calculateselectivity. The molecular weight of the resultant polymer is measuredby GPC with calibration using polystyrene standards.

(b) Copolymerization Using Complex of Example 13 as Catalyst

To a 50 mL bomb reactor, complex 40a (6.85 mg, 0.0030 mmol,monomer/catalyst ratio=50,000) obtained from Example 13 and propyleneoxide (9.00 g, 155 mmol) are introduced and the reactor is assembled.The reactor is introduced into an oil bath controlled previously to atemperature of 80° C. and is agitated for about 15 minutes so that thereactor temperature is in equilibrium with the bath temperature. Next,carbon dioxide is added under 20 bars. After 30 minutes, it is observedthat carbon dioxide is depressurized while the reaction proceeds. Carbondioxide is further injected continuously for 1 hour under 20 bars. Tothe resultant viscous solution, monomers (10 g) are further introducedto reduce the viscosity. Then, the resultant solution is passed througha silica gel column [400 mg, Merck, 0.040-0.063 mm particle diameter(230-400 mesh)] to obtain a colorless solution. The monomers are removedby depressurization under reduced pressure to obtain 2.15 g of a whitesolid. The catalytic activity of the complex used in this Examplecorresponds to a TON of 6100 and a turnover frequency (TOF) of 9200 h⁻¹.The resultant polymer has a molecular weight (Mn) of 89000 and apolydispersity (Mw/Mn) of 1.21 as measured by GPC. The polymer formationselectivity is 96% as determined by ¹H NMR.

Example 16 Recovery of Copolymer and Catalyst

In the cases of complexes 5, 7 and 10, the following process is used torecover catalysts. The colored portion containing a cobalt catalystcomponent at the top of the silica column in Example 12 is collected,and dispersed into methanol solution saturated with NaBF₄ to obtain ared colored solution. The red solution is filtered, washed twice withmethanol solution saturated with NaBF₄ until the silica becomescolorless, the resultant solution is collected, and the solvent isremoved by depressurization under reduced pressure. To the resultantsolid, methylene chloride is added. In this manner, the brown coloredcobalt compound is dissolved into methylene chloride, while theunsoluble white NaBF₄ solid may be separated. To the methylene chloridesolution, 2 equivalents of solid 2,4-dinitrophenol and 4 equivalents ofsodium 2,4-dinitrophenolate are introduced per mole of the catalyst,followed by agitation overnight. The resultant mixture is filtered toremove methylene chloride solution and to obtain brown colored powder.After ¹H NMR analysis, the resultant compound is shown to be the same asthe catalyst compound and to have similar activity in thecopolymerization.

Table 1 shows the polymerization reactivity of each catalyst.

TABLE 1 Polymerization reactivity of each catalyst^(a)

Induction M_(n) ^(d) No. Catalyst Time (min) TOF^(b) Selectivity^(c)(10⁻³) M_(w)/M_(n)  1 5  60^(e) 13,000 92 210 1.26  2 6  0 1,300 84  382.34  3 7 120^(e) 8,300 97 113 1.23  4 8  0 5,000 85 120 1.41  5 9 0  610 260^(e) 11,000 96 140 1.17  7 11 0  8 14  30 13,000 99 170 1.21  9 15 0 15,000 99 270 1.26 10^(f) 15  0 16,000 99 300 1.31 ^(a)Polymerizationcondition: PO (10 g, 170 mmol), [PO]/[Cat] = 100,000, CO₂ (2.0-1.7 MPa),temperature 70-75° C., reaction time 60 minutes. ^(b)calculated based onthe weight of the polymer containing cyclic carbonate. ^(c)calculated by¹H NMR. ^(d)measured by GPC using polystyrene standards. ^(e)inductiontime of 1-10 hours depending on batch. ^(f)polymerization using 220 g ofPO.

As can be seen from Table 1, the general compounds having iminecoordination, i.e. complexes 6, 8 and 11 has little or no polymerizationactivity. On the other hand, the complexes with a different structurehaving no imine coordination according to the present invention havehigh polymerization activity. However, complex 9 with a differentstructure having no imine coordination but containing six ammonium unitshas no activity.

Complexes 5, 7 and 10 have higher activity in order of 5>10>7, which isthe converse of order of Co-binding affinity of weak bound DNPundergoing continuous conversion/reversion between the Co-coordinatedstate and the de-coordinated state.

Complex 10 is used to perform many experiments. Under a high-temperaturehigh-humidity condition in the summer season, a great change is observedin induction time (1-12 hours). After the induction time, polymerizationrate are observed to be nearly constant (TOF, 9,000-11,000 h⁻¹). In thesummer season, the amount of water infiltrating into the dry box for apolymerization reactor is not negligible. In this case, thepolymerization system absorbs water and the induction time varies withthe amount of water. In fact, under a dry low-temperature condition inthe winter season, induction time decreases to 1 hour. In this case,when an additional amount of water is added thereto (50 equivalents vs.cobalt), induction time increases to 3 hours (entry 10). Introduction ofa significant amount of water (250 equivalents) does not allowpolymerization.

When a certain amount of water is present, the rate of polymerizationinitiation caused by an attack of DNP to propylene oxide is decreasedsignificantly, as determined by NMR (FIG. 9). When using compound 15obtained from the reaction with propylene oxide as a catalyst, it ispossible to solve the problem of such a great change in induction timedepending on the amount of water (entry 13). When using compound 15 as acatalyst, water sensitivity decreases to allow polymerization even undera [propylene oxide]/[catalyst] ratio of 150000:1, resulting in furtherimprovement in TON (entry 14). Under such a condition, complex 10 has nopolymerization activity even when using thoroughly purified propyleneoxide. Compound 15 is obtained by dissolving a high concentration ofcomplex 10 into propylene oxide and by performing a reaction for 1 hour.In this case, it is possible to neglect the ratio of [water remaining inpropylene oxide]/[compound 10].

The present application contains subject matter related to Korean PatentApplication Nos. 10-2008-0074435, 10-2008-0126170, 10-2009-0054481 and10-2009-0054569 filed in the Korean Intellectual Property Office on Jul.30, 2008, Dec. 11, 2008, Jun. 18, 2009, and Jun. 18, 2009, the entirecontents of which are incorporated herein by reference.

While the present invention has been described with respect to thespecific embodiments, it will be apparent to those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as defined in the followingclaims.

1-5. (canceled)
 6. A complex represented by Chemical Formula 6:

Wherein A¹ and A² independently represent an oxygen or sulfur atom; X(s)independently represent a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻; HCO₃⁻; or a (C6-C20)aryloxy anion; (C1-C20)alkylcarboxy anion;(C1-C20)alkoxy anion; (C1-C20)alkylcarbonate anion;(C1-C20)alkylsulfonate anion; (C1-C20)alkylamide anion;(C1-C20)alkylcarbamate anion; or anion of Meisenheimer salt with orwithout at least one of halogen, nitrogen, oxygen, silicon, sulfur andphosphorus atoms; R⁶² and R⁶⁴ are independently selected fromtert-butyl, methyl, ethyl, isopropyl and hydrogen, and R⁶¹ and R⁶³independently represent —[YR⁵¹ _(3-m){(CR⁵²R⁵³)_(n)N⁺R⁵⁴R⁵⁵R⁵⁶}_(m)](wherein Y represents a carbon or silicon atom, R⁵¹, R⁵², R⁵³, R⁵⁴, R⁵⁵and R⁵⁶ independently represent a hydrogen radical; a (C1-C20)alkyl,(C2-C20)alkenyl, (C1-C15)alkyl(C6-C20)aryl or (C6-C20)aryl(C1-C15)alkylradical with or without at least one of halogen, nitrogen, oxygen,silicon, sulfur and phosphorus atoms; or a hydrocarbyl-substitutedmetalloid radical of a Group 14 metal, wherein two of R⁵⁴, R⁵⁵ and R⁵⁶may be linked to each other to form a ring; m represents an integer from1 to 3; and n represents an integer from 1 to 20); b+c−1 represents aninteger that equals to 2×m; and A³ represents a chemical bond ordivalent organic bridge group for linking the two phenyl groups.
 7. Thecomplex according to claim 6, wherein A³ represents a chemical bond,(C6-C30)arylene, (C1-C20)alkylene, (C2-C20)alkenylene,(C2-C20)alkynylene, (C3-C20)cycloalkylene or fused(C3-C20)cycloalkylene, or —Si(R⁸⁷)(R⁸⁸)—, —CH═N-Q-N═CH—, or the arylene,alkylene, alkenylene, alkynylene, cycloalkylene or fused cycloalkylenemay be further substituted by a substituent selected from halogen atoms,(C1-C7)alkyl, (C6-C30)aryl and nitro groups, or may further include atleast one hetero atom selected from O, S and N, wherein R⁸⁷ and R⁸⁸independently represent (C1-C20)alkyl, (C3-C20)cycloalkyl,(C1-C15)alkyl(C6-C20)aryl, or (C6-C20)aryl(C1-C15)alkyl and Q representsa divalent organic bridge group for linking the two nitrogen atoms. 8.The complex according to claim 7, wherein Q represents (C₆-C₃₀)arylene,(C1-C20)alkylene, (C2-C20)alkenylene, (C2-C20)alkynylene,(C3-C20)cycloalkylene or fused (C3-C20)cycloalkylene, wherein thearylene, alkylene, alkenylene, alkynylene, cycloalkylene or fusedcycloalkylene may be further substituted by a substituent selected fromhalogen atoms, (C1-C7)alkyl, (C6-C30)aryl and nitro groups, or mayfurther include at least one hetero atom selected from O, S and N. 9.The complex according to claim 8, wherein R⁶¹ and R⁶³ independentlyrepresent —[CH{(CH₂)₃N⁺Bu₃}₂] or —[CMe{(CH₂)₃N⁺Bu₃}₂], Q in the formulaof —CH═N-Q-N═CH— represents trans-1,2-cyclohexylene or ethylene, and Xindependently represents 2,4-dinitrophenolate or BF₄ ⁻.
 10. (canceled)11. A complex represented by Chemical Formula 11:

wherein B¹ through B⁴ independently represent (C2-C20)alkylene or(C3-C20)cycloalkylene, R²⁶ represents primary or secondary(C1-C20)alkyl; R²⁷ through R²⁹ are independently selected from(C1-C20)alkyl and (C6-C30)aryl; Q represents a divalent bridge group forlinking the two nitrogen atoms; and Z¹ through Z⁵ are independentlyselected from a halide ion; BF₄ ⁻; ClO₄ ⁻; NO₃ ⁻; PF₆ ⁻; HCO₃ ⁻; and a(C6-C30)aryloxy anion; (C1-C20)carboxylic acid anion; (C1-C20)alkoxyanion; (C1-C20)alkylcarbonate anion; (C1-C20)alkylsulfonate anion;(C1-C20)alkylamide anion; (C1-C20)alkylcarbamate anion or anion ofMeisenheimer slat with or without at least one of halogen, nitrogen,oxygen, silicon, sulfur and phosphorus atoms, wherein a part of Z¹through Z⁴ coordinated at the cobalt atom may be de-coordinated.
 12. Thecomplex according to claim 11, wherein B¹ through B⁴ independentlyrepresent (C2-C6)alkylene; R²⁶ represents (C1-C7)alkyl; R²⁷ through R²⁹independently represent (C1-C7)alkyl; Q represents ethylene,trans-1,2-cyclohexylene or 1,2-phenylene; Z¹ through Z⁵ areindependently selected from 2,4-dinitrophenolate and BF₄ ⁻.
 13. Thecomplex according to claim 12, wherein B¹ through B⁴ independentlyrepresent propylene; R²⁶ and R²⁷ independently represent methyl; R²⁸ andR²⁹ independently represent butyl; Q represents trans-1,2-cyclohexylene;and Z¹ through Z⁵ are independently selected from 2,4-dinitrophenolateand BF₄ ⁻.
 14. A method for preparing polycarbonate, comprising carryingout copolymerization of an epoxide compound with carbon dioxide usingthe complex according to claim 6 as a catalyst.
 15. The method accordingto claim 14, wherein the epoxide compound is selected from the groupconsisting of (C2-C20)alkylene oxide substituted or unsubstituted by ahalogen or alkoxy; (C4-C20)cycloalkylene oxide substituted orunsubstituted by a halogen or alkoxy; and (C8-C20)styrene oxidesubstituted or unsubstituted by a halogen, alkoxy, alkyl or aryl.
 16. Amethod for separately recovering a complex, comprising: contacting asolution containing the copolymer and the catalyst and obtained by themethod for preparing polycarbonate according to claim 14 with a solidphase selected from an inorganic material, polymer material or a mixturethereof non-soluble in the solution to form a complex of the solid phaseand the catalyst and to separate the copolymer solution; treating thecomplex with an acid or a metal salt of a non-reactive anion in a mediumthat is not capable of dissolving the solid phase to perform anacid-base reaction or salt metathesis; and carrying out salt metathesiswith a salt containing anion X, wherein X is the same as defined inChemical Formula
 6. 17. The method according to claim 16, wherein thecomplex is separately recovered by adding the solution containing thecopolymer and the catalyst to a solution containing a solid phaseselected from an inorganic material, polymer material and a mixturethereof, followed by filtration; or by passing the solution containingthe copolymer and the catalyst through a column packed with the solidphase.
 18. The method according to claim 17, wherein the solid inorganicmaterial is surface-modified or non-modified silica or alumina, and thesolid polymer material has a functional group reactive to deprotonationby alkoxy anion.
 19. The method according to claim 18, wherein thefunctional group reactive to deprotonation by alkoxy anion is a sulfonicacid group, carboxylic acid group, phenol group or alcohol group. 20.The method according to claim 16, which comprises: contacting a solutioncontaining the copolymer and the catalyst and obtained by the method forpreparing polycarbonate with silica to form a silica-catalyst complexand to separate the copolymer from the solution; treating thesilica-catalyst complex with an acid or a metal salt of a non-reactiveanion in a medium that is not capable of dissolving silica to perform anacid-base reaction or salt metathesis; and carrying out salt metathesisusing a salt containing anion X.
 21. The method according to claim 14,wherein the acid is hydrochloric acid or 2,4-dinitrophenol, and themetal salt of a non-reactive anion is DBF₄ or DClO₄ (wherein Drepresents Li, Na or K).
 22. The method according to claim 14, whereinthe salt containing anion X is a salt containing Cl anion or2,4-dinitrophenolate anion.
 23. (canceled)
 24. A compound represented byChemical Formula 17:

wherein B¹ through B⁴ independently represent (C2-C20)alkylene or(C3-C20)cycloalkylene; R²⁶ represents primary or secondary(C1-C20)alkyl; R²⁷ through R²⁹ are independently selected from(C1-C20)alkyl and (C6-C30)aryl; Q is a divalent organic bridge group forlinking the two nitrogen atoms with each other; and Z⁻(s) areindependently selected from halide ions, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻, andPF_(s) ⁻.
 25. The compound according to claim 24, wherein Q represents(C₆-C₃₀)arylene, (C1-C20)alkylene, (C2-C20)alkenylene,(C2-C20)alkynylene, (C3-C20)cycloalkylene or fused(C3-C20)cycloalkylene, wherein the arylene, alkylene, alkenylene,alkynylene, cycloalkylene or fused cycloalkylene may be furthersubstituted by a substituent selected from halogen atoms, (C1-C7)alkyl,(C6-C30)aryl and nitro groups, or may further include at least onehetero atom selected from O, S and N.
 26. The compound according toclaim 25, wherein B¹ through B⁴ independently represent propylene; R²⁶and R²⁷ independently represent methyl, and R²⁸ and R²⁹ independentlyrepresent butyl; Q represents trans-1,2-cyclohexylene; and Z⁻(s)independently represent iodide anion or BF₄ ⁻.
 27. A method forpreparing a compound represented by Chemical Formula 17, comprising:adding a diamine compound to a compound represented by Chemical Formula20 to perform imination and to provide a compound represented byChemical Formula 21; and adding a tertiary amine compound thereto toproduce a compound represented by Chemical Formula 17:

wherein B¹ through B⁴, B⁹ and B¹⁹ independently represent(C2-C20)alkylene or (C3-C20)cycloalkylene; R²⁶ is primary or secondary(C1-C20)alkyl; R²⁷ through R²⁹ are independently selected from(C1-C20)alkyl and (C₆-C₃₀)aryl; Q is a divalent organic bridge group forlinking the two nitrogen atoms with each other; Z⁻(s) are independentlyselected from halide ions, BF₄ ⁻, ClO₄ ⁻, NO₃ ⁻, and PF₆ ⁻; and X³ andX⁴ are independently selected from Cl, Br and I.
 28. The methodaccording to claim 27, wherein the compound represented by ChemicalFormula 20 is obtained by reacting a compound represented by ChemicalFormula 15 with a compound represented by Chemical Formula 16 in thepresence of an acid catalyst to form a compound represented by ChemicalFormula 14, and by attaching an aldehyde group to the compoundrepresented by Chemical Formula 14:

wherein B⁹ and B¹⁰ independently represent (C2-C20)alkylene or(C3-C20)cycloalkylene; R²⁶ represents primary or secondary(C1-C20)alkyl; R²⁷ is selected from (C1-C20)alkyl and (C6-C30)aryl; andX³ and X⁴ are independently selected from Cl, Br and I. 29-33.(canceled)